Electrical question - Key on, lights lit

[galbiati]

Can someone knowledgeable in this area please explain this circuit for me. Looking at the color Delorean wiring schematic ( http://dmctalk.org/showthread.php?17-DMC-12-color-wiring-diagram ), how does the OIL and BATT lights get power when the key is turned to the 2nd click? I can't see how power gets to the lights in the cluster based off that schematic. Is this schematic complete? I am trouble shooting an electrical issue in the dash.
THANKS!
BG

PS> So I am clear, the lights are supposed to come on before you start the car to make sure they are working, mine don't, the brake light does work however, and the bulbs are good. I have not ripped the binnacle apart again yet, to see if there is power to the wires, or if the printed circuit is bad. But I'd like to know how it's getting power to test the bulbs before you start the car.

[DMC5180]

The schematic trace is missing. Short of examining the circuit board/sheet it would be difficult to determine. It does not really get power to (test) the bulbs. they just come on by default. The LOW OIL pressure light comes because the engine is not running. Therefore no pressure to open the contacts in the switch. That BATT light (aka alternator charge light) is controlled by the alternator output. Once the alternator is spinning creating Positive current flow the light goes out.

All of the instrument gauges and warning lights are powered through fuse 5.

Check your Bulkhead connectors (common point) for both systems to pass thru.

Also IF the BATT light is not illuminated you should not be able to see Charge on the gauge. The Batt light is in series with the field current circuit. No light = no charge.

[galbiati]

The LOW OIL pressure light comes because the engine is not running. Therefore no pressure to open the contacts in the switch. That BATT light (aka alternator charge light) is controlled be the alternator output. once the alternator is spinning creating Positive current flow the light goes out.

But using the color schematic shown, how does power even get into the circuit for the low oil light? It is not shown.

[Rich]

The schematic looks correct with regard to that cluster of 4 warning lamps on right of instrument cluster.

Position references here are relative to what is seen on that schematic, not actual positions in the car.

IGN switch delivers power to the AUX RELAY shown to its right in the schematic, #102.

Relay #102 in turn sends switched power down thru WU wire to Fuse #13 in the electrical bin.

Out of Fuse #13 there is a G (green) wire that feeds the inst. cluster in many places, including pin #9 on the board. That pin powers all 4 of the lamps on the right side, including the two you are asking about, OIL and BATT.

Each of those 4 lamps will light with IGN on and in conjunction with grounding of the individual circuits you can see out of pins #5, 6, 7 or 8.

That is, the wires coming out of Pins 5-8 on the cluster, right of each lamp on schematic are all switched-grounds. Those lamps are fed with a common positive on the left.

[galbiati]

The schematic looks correct with regard to that cluster of 4 warning lamps on right of instrument cluster.

Position references here are relative to what is seen on that schematic, not actual positions in the car.

IGN switch delivers power to the AUX RELAY shown to its right in the schematic, #102.

Relay #102 in turn sends switched power down thru WU wire to Fuse #13 in the electrical bin.

Out of Fuse #13 there is a G (green) wire that feeds the inst. cluster in many places, including pin #9 on the board. That pin powers all 4 of the lamps on the right side, including the two you are asking about, OIL and BATT.

Each of those 4 lamps will light with IGN on and in conjunction with grounding of the individual circuits you can see out of pins #5, 6, 7 or 8.

That is, the wires coming out of Pins 5-8 on the cluster, right of each lamp on schematic are all switched-grounds. Those lamps are fed with a common positive on the left.

Thanks for the help Rich. So, since my brake light is working and the oil and batt are not, is it safe to assume the problem lies in the printed circuit board on the back of the cluster? 16586

[Dangermouse]

Alternatively, your connector on the oil pressure switch could have come loose, or needs cleaned.

[Rich]

....since my brake light is working and the oil and batt are not, is it safe to assume the problem lies in the printed circuit board on the back of the cluster? 16586

Not quite safe to assume, just one of several poss. causes. Maybe you have them covered since your board is out.

Post #6 suggests another.

Or the lamp socket went bad. Maybe you lump those in with the 'bad board' category.

Additionally the cluster board might be OK but the cluster plug-in might have degraded on one or more connectors.

The causes can be independent of one another. Now you know where to look to see +12V to one side of each lamp socket and GND on other side. Plus what you say are known-good lamps.

[galbiati]

Not quite safe to assume, just one of several poss. causes. Maybe you have them covered since your board is out.

Post #6 suggests another.

Or the lamp socket went bad. Maybe you lump those in with the 'bad board' category.

Additionally the cluster board might be OK but the cluster plug-in might have degraded on one or more connectors.

The causes can be independent of one another. Now you know where to look to see +12V to one side of each lamp socket and GND on other side. Plus what you say are known-good lamps.

I believe the problem to be in the 16 pin connector to the printed circuit I already had to solder a few broken connectors, I might as well as do them all before I buy another printed circuit board. I dont think Im getting a good connection from the plug to the board on #9, #6, #7, #8. I'll pull it out again and see what happens. 20 degrees outside, try to get into the garage...have to get the wife out.

[DMC5180]

The schematic looks correct with regard to that cluster of 4 warning lamps on right of instrument cluster.

Position references here are relative to what is seen on that schematic, not actual positions in the car.

IGN switch delivers power to the AUX RELAY shown to its right in the schematic, #102.

Relay #102 in turn sends switched power down thru WU wire to Fuse #13 in the electrical bin.

Out of Fuse #13 there is a G (green) wire that feeds the inst. cluster in many places, including pin #9 on the board. That pin powers all 4 of the lamps on the right side, including the two you are asking about, OIL and BATT.

Each of those 4 lamps will light with IGN on and in conjunction with grounding of the individual circuits you can see out of pins #5, 6, 7 or 8.

That is, the wires coming out of Pins 5-8 on the cluster, right of each lamp on schematic are all switched-grounds. Those lamps are fed with a common positive on the left.


Sorry Rich, Fuse 13 is for Automatic transmission ONLY. Out of Fuse 5 is a green wire that provides power to the cluster including Pin 9.

The Pin 9 Trace on the PC supplies power to the OP Gauge then continues on to the RH cluster warning lights. If the Key is ON does the OP gauge needle sit at ZERO or below it. This should confirm the pin 9 trace connection one way or the other.

[Rich]

Sorry Rich, Fuse 13 is for Automatic transmission ONLY. Out of Fuse 5 is a green wire that provides power to the cluster including Pin 9.

The Pin 9 Trace on the PC supplies power to the OP Gauge then continues on to the RH cluster warning lights. If the Key is ON does the OP gauge needle sit at ZERO or below it. This should confirm the pin 9 trace connection one way or the other.

Got it. Right you are. I crossed up the 2 GRN wires as they headed across the schematic from the cluster to the fuse bank, picked up the wrong fuse over there.

Thanks.

[galbiati]

FIXED!

#9 Pin (green wire) 12v Power, wire had power at back of cluster, but tab on printed circuit board was cracked across not giving power to the 4 warning lights (BRAKE, FUEL, BATT, OIL). Little bit o' solder, and fixed. Thx for help guys. BG

[galbiati]

The schematic trace is missing. Short of examining the circuit board/sheet it would be difficult to determine. It does not really get power to (test) the bulbs. they just come on by default. The LOW OIL pressure light comes because the engine is not running. Therefore no pressure to open the contacts in the switch. That BATT light (aka alternator charge light) is controlled by the alternator output. Once the alternator is spinning creating Positive current flow the light goes out.

All of the instrument gauges and warning lights are powered through fuse 5.

Check your Bulkhead connectors (common point) for both systems to pass thru.

Also IF the BATT light is not illuminated you should not be able to see Charge on the gauge. The Batt light is in series with the field current circuit. No light = no charge.

I think the problem is in the field current circuit now, still not charging with new alternator. Volt guage shown voltage dropping slowly, BATT light is not lit. At battery it shows 11.88 volts and at back of alternator it shows the same, 11.88volts. Same as the old one. I have to get this back in the garage, its 11 degrees out.

[Rich]

...still not charging with new alternator. Volt guage shown voltage dropping slowly, BATT light is not lit. At battery it shows 11.88 volts and at back of alternator it shows the same, 11.88volts. Same as the old one. I have to get this back in the garage, its 11 degrees out.

Even good/new alternators won't work if there is a wiring/ground problem. You should be seeing >13V in the system at idle with few accessories on and a battery that's halfway decent. The fact that the old and new alternator behave the same way suggests your problem isn't specifically the alternator. You probably figured that one out already.

That BATT lamp isn't by chance an LED, is it? And it's a known-good lamp? The lamp is known to be a vital part of the charging circuit.

Your alternator, old or new, might not have worked well without that lamp correctly placed in the circuit.

[Dangermouse]

Just a thought. What alternator do you have?

There was a discussion on here recently about Herveys 140A alternators not charging well at idle, but once the revs increase, all is well. I don't recall a comment about whether the lamp was illuminated during idle conditions.

[galbiati]

I have a regular bulb in the dash, no led. The whole printed circuit was soldered where breaks were located. It tested good off the vehicle. All of the ends of the plug check good off of the back of the dash, so the problem is elsewhere. I believe the problem lies in the alternator not receiving a signal to charge. I have yet to get it in the garage, maybe later this morning and I can check some circuits, and bulkhead connectors.

[Ron]

Try this:
With key On, engine OFF, disconnect the Brown/Yellow field wire at the alternator and ground it. If the battery light comes ON, your field circuit is OK. You can put 12V on the alternator's field terminal and see if the battery voltage raises to confirm it is not the alternator (Note, once you do this, depending on the internal regulator's style, it may charge correctly even after removing the 12V until you turn the key off or the regulator sees the battery is fully charged. So don't let it fool you into thinking you have an intermittent problem... Also, revving the engine once will cause most of the "aftermarket" regulators to kick in even if the field is disconnected.)
Which alternator do you have?

Check the Brown/Yellow wire's connection at the 7 Pin White Bulkhead Connector.

[galbiati]

I just pulled it in the garage, I'll let you know what I find out shortly. Thanks again.

[galbiati]

Try this:
With key On, engine OFF, disconnect the Brown/Yellow field wire at the alternator and ground it. If the battery light comes ON, your field circuit is OK. You can put 12V on the alternator's field terminal and see if the battery voltage raises to confirm it is not the alternator (Note, once you do this, depending on the internal regulator's style, it may charge correctly even after removing the 12V until you turn the key off or the regulator sees the battery is fully charged. So don't let it fool you into thinking you have an intermittent problem... Also, revving the engine once will cause most of the "aftermarket" regulators to kick in even if the field is disconnected.)
Which alternator do you have?

Check the Brown/Yellow wire's connection at the 7 Pin White Bulkhead Connector.

#5 fuse has power with key on. Brown/yellow wire at alternator goes into a plug with a red wire coming out going to the back of alternator. With engine off there is power at the back of the alternator. I disconnected that red wire (which comes out of the alternator plug) and grounded it and no light lit on the dash with the key on. I am now going to put a hot wire from the + battery lead to the back of the alternator to see what that does with the red wire back on as well.

[Ron]

If there is no power on the Brown/Yellow wire when the key is on, that is the problem!
Did you check the connection at the bulkhead connector?
Can you post a pic of the back of the alternator (including ALL the wires connected to it)?

[galbiati]

Ran a + line to back of alternator off of + terminal, no change, 11.73 volts at battery.

[galbiati]

Definitely no power to brown/yellow wire going to alternator. I put the needle end of tester right through the wire and grounded the other end with key on.

[galbiati]

According to the Alternator Circuit Wiring Diagram on here, the brown/yellow wire comes from the back of the cluster, off of the #5 fuse. I can't believe that the whole car is crippled from a bad connection at the printed circuit board.

[Ron]

Ran a + line to back of alternator off of + terminal, no change, 11.73 volts at battery.
No...you have to put 12V on the terminal that the Brown/Yellow wire goes to...

Also, you have to refresh your browser for other's new messages to show up.


Definitely no power to brown/yellow wire going to alternator. I put the needle end of tester right through the wire and grounded the other end with key on.
This is not a good test...depending on difference between the rating of the Battery Bulb and the tester bulb, you never know which one will light up...
Use a jumper wire and watch the Battery Bulb.


According to the Alternator Circuit Wiring Diagram on here, the brown/yellow wire comes from the back of the cluster, off of the #5 fuse. I can't believe that the whole car is crippled from a bad connection at the printed circuit board.
That's the way almost all cars are ;-)

Slow down...reread the posts above and follow them exactly..

[galbiati]

Well I pulled out my cluster again. I took my test light on pin#9 (green 12v power) and jumped it to the #7 (Batt warning light) terminal, turned the key on and nothing, nothing for any of the terminals, including 5,6,7 and 8. (brake low fuel, batt and oil) There is def power on #9 when I test ground...

[Ron]

Well I pulled out my cluster again. I took my test light on pin#9 (green 12v power) and jumped it to the #7 (Batt warning light) terminal, turned the key on and nothing, nothing for any of the terminals, including 5,6,7 and 8. (brake low fuel, batt and oil) There is def power on #9 when I test ground...
For each of those, if a bulb was not lit just before you tested it, your tester light would not light...and even then it might not, again depending on the bulb rates.

PM me your phone #

[Exolis]

I never use the little light probe thing so I can't give you any advice there, but I would just use an ohm meter then measure between the pin at the connector to meter all the way to the connector to the sensor. Should be less than 1 ohm. Than do ohm measurement from Pin 9 to (273) or + side of the Light bulb for Oil, than both terminals of the light bulb with bulb in place(should be a few ohms), than the negative side of the bulb to pin 7. That will tell you if the meter is broken.

You also need to put your battery on a charger as it's essentially dead.

[galbiati]

For each of those, if a bulb was not lit just before you tested it, your tester light would not light...and even then it might not, again depending on the bulb rates.

PM me your phone #

I hooked up the oil switch which was disconnected and taped up, the oil light now comes on with the key. The brake light comes on with the e-brake on and with the master cylinder lid open. Still can't get the battery light to come on, or to charge. I am taking the alternator off and getting a new one.

[Ron]

Take both of them...

[Dangermouse]

I hooked up the oil switch which was disconnected and taped up, the oil light now comes on with the key.

A Ha !!!

I got one right :) :rofl:

Though if it was disconnected and taped up, I would assume that the switch is bad and the PO was annoyed by the light being on (or the oil pressure never gets high enough to operate the switch :umm:)

[Dangermouse]

Just a thought. What alternator do you have?

There was a discussion on here recently about Herveys 140A alternators not charging well at idle, but once the revs increase, all is well. I don't recall a comment about whether the lamp was illuminated during idle conditions.

Before you head off to autozone, did you check this?

[Ron]

The new alternator will not turn the light on but he can now ground the Brown/Yellow wire and the light comes ON.
FWIW, the circuit will handle lighting both the BAT bulb and tester bulb (to ground).

[galbiati]

The new alternator will not turn the light on but he can now ground the Brown/Yellow wire and the light comes ON.
FWIW, the circuit will handle lighting both the BAT bulb and tester bulb (to ground).


Just verified this again, I ran a ground jumper from the engine/frame ground (right rear) to the brown/yellow wire, BAT light comes on. So, why isn't my brown/yellow wire grounded when the alternator and engine are not running?

[Ron]

Since the B/Y wire will burn both bulbs in series to ground , and, bringing 12V to the regulator showed ~11V and falling, I'm guessing the regulator is not doing its job.

[galbiati]

1672516726

Just showing the lights now on with the jumper from the engine/frame ground (-) to the brown/yellow wire in the plug, with the plug OUT OF the alternator.

[Ron]

LMAO...Go to AutoZone dude!

Sorry...

[galbiati]

LMAO...Go to AutoZone dude!

Sorry...

New alternator is installed. Same results, not charging, no light when I turn the key.. I had it checked before I left the store as well. Is there a relay somewhere that I missed?

[galbiati]

A Ha !!!

I got one right :) :rofl:

Though if it was disconnected and taped up, I would assume that the switch is bad and the PO was annoyed by the light being on (or the oil pressure never gets high enough to operate the switch :umm:)

Actually the oil pressure light goes out after the car starts, so it was just disconnected for no reason..The plug end was missing, so I crimped a new one on and OIL light is fixed. Thanks i actually noticed my rpm's are now down to 900. They used to be 1100-1300.

[Dangermouse]

Well that's one piece of good news. Well done.

[Ron]

Confirm that disconnecting the plug and grounding the B/Y wire turns the BAT light on (w/ Key ON). If so, compare the old replacement plug to the new replacement pigtail...see if one has a wire connected to the "L" while the other has a wire to the "F" (There are 2, 3 and 4 wire versions...your need one that uses the "S" and "F", Sense and Field, abandon any other wires).
A full plug should be situated like this-
(S)ense [larger connector than other three, connect to main post with large Brown wires], (F)ield [connect to B/Y wire,], (L)ight [ignore], (P)ulse [ignore]

In any case, you want the Brown/Yellow wire going to the alternator "F" (instead of the "L"). The "S" goes to the main stud on the back of the alternator.

[galbiati]

Confirm that disconnecting the plug and grounding the B/Y wire turns the BAT light on (w/ Key ON). If so, compare the old replacement plug to the new replacement pigtail...see if one has a wire connected to the "L" while the other has a wire to the "F" (There are 2, 3 and 4 wire versions...your need one that uses the "S" and "F", Sense and Field, abandon any other wires).
A full plug should be situated like this-
(S)ense [larger connector than other three, connect to main post with large Brown wires], (F)ield [connect to B/Y wire,], (L)ight [ignore], (P)ulse [ignore]

In any case, you want the Brown/Yellow wire going to the alternator "F" (instead of the "L"). The "S" goes to the main stud on the back of the alternator.

F I X E D ! (FINALLY)

Bad connection inside the plug (intermittent). It uses the S and L posts. I bent the L tab out a little bit and bingo, light is on and charging well above 13v. Thanks for all the help Ron!

[Ron]

Great -- NP! ...a lot was eliminated before my $.02 tho.


For future readers, when converting some Saturns use S & L, -- Some use S and F. If you do it wrong, it shouldn't hurt anything, but I have read where if you use 12V w/o it going through the bulb, it may pop the regulator...not sure why that would be...
Notes:
GM's CS pigtail will allow you to wire it either way (cheap at AutoZone).
1G uses 2 wires in the plug
2G uses 4 wires in the plug

If I get to the bottom of using L v/s F, I'll post it here (I'd GUESS the F would work here as well tho).

[galbiati]

Great -- NP! ...a lot was eliminated before my $.02 tho.


For future readers, when converting some Saturns use S & L, -- Some use S and F. If you do it wrong, it shouldn't hurt anything, but I have read where if you use 12V w/o it going through the bulb, it may pop the regulator...not sure why that would be...
Notes:
GM's CS pigtail will allow you to wire it either way (cheap at AutoZone).
1G uses 2 wires in the plug
2G uses 4 wires in the plug

If I get to the bottom of using L v/s F, I'll post it here (I'd GUESS the F would work here as well tho).

I didnt change anything on the plug, I only soldered the connection as the PO had it twisted with electrical tape. It uses S and L. Only thing special I did with the Saturn alternator was I had to put in a 1/2 spacer behind the front top lobe to take up the slack on the factory pivot bracket. The back lobe had a bushing in it that I had to drill a bit bigger to accept the factory bolt. Without that 1/2" spacer the alternator would be sliding front to back on the pivot bolt. Other than that, it was about $120 for the new alternator with a limited lifetime warranty. Oh yeah you have to change the pulley as well as it comes with a serpentine pulley, (easy).

Thanks again Ron! Now off to the next hurdle, cooling fans not working! I'll start a new thread for that one.