Troubleshooting cooling fan

[DMC-Ron]

I was installing Dave's electronic fan relay when I noticed my front left fan (original fans still in car) was not running. Nothing to do with the new electronic relay (which works great). So I did some troubleshooting:

1. Unplugged the left fan and connected it to a portable 12 VDC source - fan runs just fine.
2. Measured the voltage at the plug supplying current to the fan (with fan disconnected - multi-meter probes in plug). Indicated 6.8 volts.
3. Measured the voltage from the positive plug prong to frame ground of car. Same, 6.8 volts.
4. Measured ohms resistance from negative prong to frame. Low, around 0.3 ohms.
5. Measured voltage leaving the fan fail socket (I still have fused jumpers in socket) with negative lead referenced to negative battery post. 12.5 volts.

A little perplexed about the voltage drop. How could I get 6.8 volts at the fan connector with just the multi meter plugged in (essentially no load)? The right fan is working normally. Ran out of time (how's that possible with a DeLorean?) and had to put this aside for later. Perhaps someone has a tip on this.

Thanks,
Ron

[Bitsyncmaster]

Yes that is very strange to see a voltage drop without a load connected. Are you sure your meter did not auto range to another scale so you did not really see 6.8 volts?

[Ron]

5. Measured voltage leaving the fan fail socket (I still have fused jumpers in socket) with negative lead referenced to negative battery post. 12.5 volts.

Did you check it at the socket's terminal itself (v/s the terminal that plugs into it from the fused jumper)?

I'd try connecting everything up then swapping the two fused jumper terminals....
Or, bypassing the socket's terminal by applying 12V to the BG wire immediately after it...

[Bitsyncmaster]

Most fuses you can touch a pointed meter probe on the little metal tabs on the top of the fuse to measure the voltage under load.

[DMC-Ron]

Ron and Dave,
Good suggestions. It occurred to me that the connector in the fan relay socket might have backed out. I felt underneath and there didn't seem to be anything pushed back. From the top it looks fine. I'll check it again then measure it under load. I'm also going to extend a wire to the battery ground lug so I can see actual plus voltage at the fan plug. Later, I can switch and use the same wire for the + voltage and tap from the relay socket to the fan.

The multi-meter is new to me (I purchased one with dwell) but it is not auto-scale, so I think the 6.8 volt reading was valid. I'll verify with my fluke.

Later,
Ron

[Bitsyncmaster]

Ron and Dave,
Good suggestions. It occurred to me that the connector in the fan relay socket might have backed out. I felt underneath and there didn't seem to be anything pushed back. From the top it looks fine. I'll check it again then measure it under load. I'm also going to extend a wire to the battery ground lug so I can see actual plus voltage at the fan plug. Later, I can switch and use the same wire for the + voltage and tap from the relay socket to the fan.

The multi-meter is new to me (I purchased one with dwell) but it is not auto-scale, so I think the 6.8 volt reading was valid. I'll verify with my fluke.

Later,
Ron

I have used a long meter jumper wire to find voltage drops for my fuel pump. It's a great way to get the ground reference clipped right on the battery terminal so you can find voltage drops with one solid reference point.

[DMC-Ron]

A little further troubleshooting on this issue and I have found that I have 22K ohm resistance in the wiring from the fan fail relay socket to the + side of the fan connector.

But let me back up a bit. Previously I found that if I injected +12 volts into the fan connector the fan would run. This verified the fan ground was fine (I thought for sure it was probably a grounding issue). Here is the probe supplying +12 to the fan (nothing disconnected at this point):
54612

If I connect my meter at the fan fail relay and the disconnected fan plug for a continuity test I see the 22K ohms of resistance:
54611 54613

So my questions: Would it seem likely that the resistance is a poor connection? What would be the most likely cause and location for this issue (bad connection??)? This is the left cooling fan green/black wire between the fan fail relay and the left cooling fan connector. When I look at the wiring schematic, I see connector designations shown but it's not clear if the represented connectors are in the wiring harness or if the connector shown in the circuit represents the connector right at the cooling fan. More to the point, are there any connectors in the wiring harness I should focus on?
54614

I would appreciate your suggestions,
Ron

[Bitsyncmaster]

The fan wires run from the fan fail socket up to the connectors near the washer bottle. Your bad connection could be the contact area of those washer bottle pins or a crimp on those pins. It could also be the crimp on the fan fail socket pin or the two pin fan connector pin.

The washer bottle connectors are a pain to get at so I would start with new pins on the two pin fan connectors and fan fail socket pins.

Note the stock wiring is non-plated copper wire so when I replace a pin, I sand paper the striped wire to get clean copper.

[Ron]

The connection near the washer bottle would be my guess for a bad connection causing it. But, like Dave,
I'd eliminate the rest first...Maybe get a couple of straight pins and pierce the ends of the Black/Green and Black/Orange wires immediately behind where the connectors crimp to the wire and take a reading.


Probably nothing, but just to be sure- In the 3rd pic, the Red wire in the fan fail socket goes to the meter's
probe lead, and, the meter's common connection is not in a pic. I.E. The Black wire shown is NOT going the meters common lead, but into the cooling fan relay socket from a previous test??

[DMC-Ron]

The fan wires run from the fan fail socket up to the connectors near the washer bottle. Your bad connection could be the contact area of those washer bottle pins or a crimp on those pins. It could also be the crimp on the fan fail socket pin or the two pin fan connector pin.

The washer bottle connectors are a pain to get at so I would start with new pins on the two pin fan connectors and fan fail socket pins.

Note the stock wiring is non-plated copper wire so when I replace a pin, I sand paper the striped wire to get clean copper.

Dave,
OK. I'll take a closer look at the relay pins and the fan connector. But just from looking they seem fairly good, at least not a lot of corrosion.

Here's a close look at the fan fail relay socket:
54630

Another odd thing that has me scratching my head is the connector at the left fan. The connector appears to have two wires connected to each pin. It looks like the power wire (black-green) comes into the connector then cascades out heading somewhere else? Same with the ground wire. Why would there be two and where are they going? I may just not be seeing this correctly. Perhaps when I clean up the wiring area it will look different Here's a picture in hopes that you can see what I'm talking about:
54631

Also I notice that the fan connector is coated with a protective grease. The Good news is that there is no corrosion. I like to use Corrosion X on electrical connectors but I know others use various conductive grease products. Here's a photo:
54632

Anyone have pictures of the connector at the washer bottle?

Thanks, Ron

[DMC-Ron]

The connection near the washer bottle would be my guess for a bad connection causing it. But, like Dave,
I'd eliminate the rest first...Maybe get a couple of straight pins and pierce the ends of the Black/Green and Black/Orange wires immediately behind where the connectors crimp to the wire and take a reading.


Probably nothing, but just to be sure- In the 3rd pic, the Red wire in the fan fail socket goes to the meter's
probe lead, and, the meter's common connection is not in a pic. I.E. The Black wire shown is NOT going the meters common lead, but into the cooling fan relay socket from a previous test??

Sorry for not showing the full connections. The meter is "ohming" out the left fan wire. The meter's red lead is connected to the jumper wire inserted into the fan fail socket while the common lead is connected (via a long jumper) to the black/green pin of the disconnected fan connector at the front of car.

Ron

[Ron]

NP! ...you posted the meter and other end...I was hesitant to ask but ya never know...

Did you know the schematic you posted above is not like stock?

[DMC-Ron]

NP! ...you posted the meter and other end...I was hesitant to ask but ya never know...

Did you know the schematic you posted above is not like stock?

Odd, it was right from the DeLorean electrical schematic?? Are there other versions of the schematic? Or is the electrical schematic just incorrect for this specific circuit?
Ron

[Ron]

AH, now we're onto something....

BRB...

[DMC-Ron]

AH, now we're onto something....

BRB...

Here is the other schematic I have from the schematic documents of specific systems:
54634

The one I previously posted was from the large full-car schematic.

Ron

[Ron]

I've looked at A LOT of schematics and have never seen it any other way than this:

54637
(Click to enlarge)

[DMC-Ron]

AH, now we're onto something....

BRB...

EDIT:
I've look at A LOT of schematics and have never seen it any other way than this:

54633
(Click to enlarge)

I agree that this one is clearer (and agrees with the second one I posted). The only large difference I immediately notice is that the full car schematic shows the right fan wire as Black/Orange. This is not correct for my car as both of my fan wires leaving the fan fail socket are black/green.

Ron

[Ron]

Yep, your car's Black/Green is like the one I just posted. The last one you posted has a Black/Orange feeding the Fan Fail (not the breaker, which isn't shown...) instead of Brown/Slate.

Where did you get that schematic? It's color so I know it isn't DMC LOL

[David T]

Yep, your car's Black/Green is like the one I just posted. Another difference is your's has a Black/Orange feeding the Fan Fail (not the breaker, which isn't shown...) instead of Brown/Slate.

Where did you get that schematic? It's color so I know it isn't DMC LOL

Get out your Workshop Manual and open it up to M:18:10. It is a really simple circuit.

[Ron]

Get out your Workshop Manual and open it up to M:18:10. It is a really simple circuit.
Me? ...It's wired the same as the one I posted.
J/K!
=============================


Ron, I think the first one IS ~DMC, remastered color...(How B/G got changed is a mystery ;-)
It also has the Fan Fail as 112, which is the Fan Relay.

The second one Sean made. (Shows B/O feeding Fan Fail.)
The one I use did have BO between the cooling fan and the breaker, instead of N/O.

I made notes/corrections where I could.
I can't verify since my D is getting a stage 2 engine courtesy of its new owner. Dave can for sure.
I'm still going with two straight pins...on the way to the washer bottle :devil:

[Bitsyncmaster]

Me? ...It's wired the same as the one I posted.
J/K!
=============================


Ron, I think the first one IS ~DMC, remastered color...(How B/G got changed is a mystery ;-)
It also has the Fan Fail as 112, which is the Fan Relay.

The second one Sean made. (Shows B/O feeding Fan Fail.)
The one I use did have BO between the cooling fan and the breaker, instead of N/O.

I made notes/corrections where I could.
I can't verify since my D is getting a stage 2 engine courtesy of its new owner. Dave can for sure.
I'm still going with two straight pins...on the way to the washer bottle :devil:

I'm pretty sure my car had black/orange on my removed fan circuit breaker. I have found a few locations of differences of wire color on my car so don't be to concerned where yours don't match the schematic colors. The two wires on the fan connectors is the connection of the capacitors. The capacitors are taped to the harness not far from the fan two pin connectors.

[BABIS]

I'm pretty sure my car had black/orange on my removed fan circuit breaker.

same here!

[Ron]

I'm pretty sure my car had black/orange on my removed fan circuit breaker.


same here!

B/O going in and out of the breaker?

EDIT: NM.
I did an image search for "fan circuit breaker" and most show N/O to Fan Relay and B/O to the Fan Fail. None with N/S like the WS manual.

Best pics:
54639

54638

[DMC-Ron]

OK. I need to know more about this connector at the washer bottle for the cooling fan wiring.

I confirmed that the fan fail socket connector is fine, yet the full voltage is not getting to the black/green at the fan connector. I used a needle probe with my multi-meter to verify this. The needle probe allows you to pierce the insulation and make contact with the conductor. It is a very sharp, very slim needle. It does leave a small puncture but that can be easily sealed. For certain troubleshooting, it is easier than removing and re-crimping new connectors. I connected +12 into the relay fan socket connector for the left fan, found that I had +12 (12.4 volts actually) in the black/green leaving the socket but only had 0.14 volts in the black/green wire just ahead of the fan connector.

Here is a photo of my test connection at the wire leaving the fan fail relay socket:
54704

Photo of test connection and voltage at the fan connector:
5470254703


How do you get at this connector at/near the washer bottle? Any pictures, suggestions, how to’s?

Thanks, Ron

[Bitsyncmaster]

How do you get at this connector at/near the washer bottle? Any pictures, suggestions, how to’s?

Thanks, Ron

I think the best way to get at the connectors is to remove the drivers side headlight bucket. I think there is enough harness to pull the connectors into view that way.

[DMC-Ron]

I think the best way to get at the connectors is to remove the drivers side headlight bucket. I think there is enough harness to pull the connectors into view that way.

Dave,
Here are a couple of pictures from another thread where Johnathan has removed his front fascia. Does the connector I'm looking for show up in these photos?
54720

54721

Thanks,
Ron

[Bitsyncmaster]

Dave,
Here are a couple of pictures from another thread where Johnathan has removed his front fascia. Does the connector I'm looking for show up in these photos?
54720

54721

Thanks,
Ron

You would need to pull that grommet out. I think the harness has enough wire to pull the connectors through the hole where the grommet is. I seem to remember replacing some pins when I had the bucket removed

[dmcnc]

My Headlight pin connectors at that same harness connector by the washer bucket were heavily corroded a few years ago - same issue: almost no voltage at the bulb connectors. The holes on the bottom sometimes clog up and the bucket fills up with water outside the washer bottle. You can imagine what that'll do to your connectors. IF that's the case, widen the holes with a drill before you reinstall.

[Ron]

I never had to get into that area but maybe the first few pics HERE (http://dmctalk.org/showthread.php?3763-The-Restoration-of-1768&p=65634&viewfull=1#post65634) will help.

[DMC-Ron]

Ron, thanks for the photos they are very helpful and at least got me orientated on where this washer bottle tub actually is.


Dave, I think I see what you're saying. With the help of Ron's photos I found a depiction of the harness in the parts manual.

I believe the highlighted connector is the suspect one that I'm hoping access and check:
54724

And looking at the harness behind the left headlight I see that pulling the headlight harness forward might also pull forward the connector going to the fans (wishful thinking?). But in the sketch it seems like it would require a lot of slack to get the connector to the front where I can work on it.
54725

Would a better approach be to remove the washer bottle tub and see if I could get access there? I think I can see the actual connector in Ron's photo:
54726

[Bitsyncmaster]

I pulled my washer bottle a long time ago and I remember I could not do much with the connectors since they are way up at the top. Maybe if you disconnect the connectors than you can pull the main harness down.

Now I did some rewiring in the headlight area and I think I was able to disconnect the connector for the front harness (headlights and blinkers) from that hole under the light bucket. But I'm not sure if you could get the other connectors that way.

[cis6409]

I had to replace my front main loom and was able to pull the grey grommet out of the hole beside the washer bottle by squeezing and manipulating it..
Once I did that I was able to access the loom connector , once I pulled the connector apart there was enough slack in the loom in the the pontoon side to pull it down and access the pins on the other side of the
plug ..

It is tight but i was able to pull it down enough to get access to pins ..
I had to to do it this way cause the washer bottle bolts were spinning in the fibreglass , just took the front drivers wheel off was the only other thing I done
Hope this helps
Cheers
Shane

[cis6409]

"I believe the highlighted connector is the suspect one that I'm hoping access and check:
54724"


This is the same connector and grommet I had to work with, beside the washer bottle but accessed from underneath

Shane

[DMC-Ron]

Encouraging. Thank you Shane. I'll give it a go. Ron

[DMC-Ron]

I'm back working on the cooling fan issue. If you haven't followed along the problem is my left side cooling fan. The motor is fine it's just not getting enough voltage to run. I previously verified that the problem was the wiring. Somewhere there is a bad connection between the fan fail relay socket and the connector at the fan. It was pointed out the there was a connector in the bottle washer tub that may be the culprit. I would have never known except for the help of this forum. So I got the tub off (you have to be careful and patient with the bolts or the nutserts will break loose and start spinning). Sure enough, there was the connector and using my meter I verified it was the problem. Here are some photos:

Here is the connector after pulling it down from the chamber above the washer bottle tub:
55986

Here is the culprit, a failed connector pin:
55983

You can see several of the other pins are also in poor condition.

On the male end the pins are showing corrosion:
55984

I was able to clean up the male pins pretty well:
55985

I cleaned the female pins with less success, so I would like to get replacements. Where can I get the female pins? I don't need hundreds, just a few. How do you extract the pins from the socket? Is there a tool?

Sincerely,
Ron

[Bitsyncmaster]

Original pins are pretty hard to find. I have some if you only need a few. The female pins are a pain to pull even with my pin extractor but they eventually pull out with some pulling and twisting while using my extractor. Then of course you should have the open barrel crimper.

[DMC-Ron]

Original pins are pretty hard to find. I have some if you only need a few. The female pins are a pain to pull even with my pin extractor but they eventually pull out with some pulling and twisting while using my extractor. Then of course you should have the open barrel crimper.

Dave,
If I were to replace all the pins, I would need 9 pins:
55983

Looking at the condition after I cleaned them, I think I can get by without replacing all 9. If I am interpreting the wiring harness sketch correctly this connector serves the following:
55987

1. cooling fans
2. horns
3. fuel pump ??
4. hood light
5. another item that I'm not sure about - perhaps the low brake fluid switch

Of the list above, only the cooling fans and fuel pump draw high amps. So perhaps I only need 4 or 5 pins. What do you think, do I have the right loads listed for this connector? I can PM you if you like to see about a few pins and ask about the extraction tool.

Thanks,
Ron

[Bitsyncmaster]

Dave,
If I were to replace all the pins, I would need 9 pins:
55983

Looking at the condition after I cleaned them, I think I can get by without replacing all 9. If I am interpreting the wiring harness sketch correctly this connector serves the following:
55987

1. cooling fans
2. horns
3. fuel pump ??
4. hood light
5. another item that I'm not sure about - perhaps the low brake fluid switch

Of the list above, only the cooling fans and fuel pump draw high amps. So perhaps I only need 4 or 5 pins. What do you think, do I have the right loads listed for this connector? I can PM you if you like to see about a few pins and ask about the extraction tool.

Thanks,
Ron

I sent you a PM. Another possibility is you can get a new connector with new pins and that would let you just cut the old one out without the need to extract the pins. The new pins are not compatible with the OEM connector shell. By new pins i mean the 3M made pins that are available.

[David T]

Or just cut out the plugs and solder the wires together. Unless you are concerned with originality that connector is not necessary.

[DMC-Ron]

Or just cut out the plugs and solder the wires together. Unless you are concerned with originality that connector is not necessary.

David,
That's a good thought and I had considered it. Doing so would eliminate the issue of failed connector pins in a connector that is very difficult to access. But it would also capture the harness thru the washer tub. I had also considered just putting on bullet connectors. I've had good luck with them on other cars. For now, I'm going to stick with the original connector. Dave is going to lend me his extractor tool and provide a few pins...thanks Dave!

Ron

[DMC-Ron]

Left fan issue is resolved! Thanks to Dave for lending me the extractor tool and some spare pins. And thanks to everyone else that provided advise, photos, and suggestions. Here's the final fixes:

Used Dave's extractor tool. Took a little wiggling but it worked great getting out the burnt cooling fan pins.
56246

Crimping the new connector pin:
56247

Once the wiring was all sorted, I installed Toby's low amperage fans:
56248

I LOVE the new fans. They are much quieter and have a much nicer tone. Once the new fans were in and working, I installed Dave's fan fail relay (had just stuck with the fuse jumpers while sorting out the problem with the original fans). I really like Dave's fan fail relay. It delay sequences the fans. So what you get is the first fan starting, getting to full speed, then after a short delay, up comes the second fan. Sounds kinda cool! Plus the relay lights up the fan warning light should a fan (or fans) fail. Or it should if my fan fail light was functional. Sadly, it's not. So, another thing to sort!!

By the way, the fans were installed during an Northwest tech session with the help of Toby. You do the work but Toby looks things over and offers suggestions and advice. Now an then he just can't stand it and he'll grab a wrench. The tech sessions are great!

One last thing that was surprising about the original fans. They are four bladed fans but the four blades are not evenly spaced. Just seemed a bit odd:
56249

Anyway, thanks again for all who helped.
Ron

[cis6409]

Well done!
great to hear it resolved very satisfying when you get to the bottom of annoying problem like that ..


Shane

[DMC-Ron]

Turned out the non-functional fan fail indicator was simply a burned out bulb. Replaced it with an LED version and with Dave's electronic fan fail relay, I now have a real fan fail warning system. If I disconnect a fan (tested both) the fan fail light will give continuous single blink. If I disconnect both fans, it does a double blink. Very nice! And I think the blinking will draw more attention than just having a light come on. My only wish would be for a way to test the indicator. I could add a button back in the relay compartment but it would take a bit of wiring. I don't know if the module has a diagnostic method to trigger the indicator for test purposes. In any case, I'm pleased to have something that actually monitors the fan operation and will provide a noticeable alert if there is a failure.

Now on to a new issue. I ordered and received some white LED bulbs to replace the climate panel's general back-lighting. Ordered the bulbs from superbriightled.com and, by the way, of 5 bulbs, 2 were bad (first time for SBLED). The LED bulbs are polarity sensitive, but they come with the case negative so they work fine for this application. Here's the issue: With the climate face-plate removed I had easy access to the four bulbs used for back-light, but when I tried to remove the bulb the socket just pushed back. Are the back-light bulbs intended to be pulled out from behind and replaced similar to the way the three warning lights pull back from the face-plate? If so, can this be done without removing the console cover?

Thanks,
Ron

[cis6409]

remove the bulb the socket just pushed back. Are the back-light bulbs intended to be pulled out from behind and replaced similar to the way the three warning lights pull back from the face-plate? If so, can this be done without removing the console cover?

Yes. and no for the second part .

remove the cover - (the center housing tunnel I mean )so you can see more easily what your doing and you don't accidentally pull off another wire or vacuum hose going to the mode switch - it can be a real rats nest of wires back there with all the connections to the switches to navigate around them to get to the illumination bulbs
But shouldn't be too much hassle



Cheers
Shane