Fans Turn on Even Though Car Not Running

[lazabby]

The other day I and others were doing some work on my car. We had the ignition in the "on" position but the motor was not running. The AC began cycling and the fans would come on and off even though the car was not hot. The fans would come on when the AC kicked on. I have the Joe Cool controller. What would make the fans come on and off like that? Is it something with the Joe Cool controller which controls the fans?

[dmc6960]

Thats exactly what its supposed to do. The AC needs the fans to operate, so by design, whenever the AC compressor is engaged the fans go on as well. When the engine is cool enough to not call for additional cooling, the fans will cycle with the compressor.

[WelmoedJ]

While in IGN ON, turn the A/C selector to OFF and the fans will stop turning.
Simple as that.

[Ron]

Thats exactly what its supposed to do. The AC needs the fans to operate, so by design, whenever the AC compressor is engaged the fans go on as well. When the engine is cool enough to not call for additional cooling, the fans will cycle with the compressor.I'm wondering why the compressor would be "cycling" with the engine off in the first place? It shouldn't.
I've never played with a Joe Cool setup, but it sounds like the culprit to me...

[Bitsyncmaster]

I think the question is "when you cycle the AC via switching the mode switch to AC" then the fans come on. Yes that would be normal operation.

Note: Not good to leave your key in the on position for to long without starting the engine. Many things get powered and will quickly drain your battery. Stock ignition and idle system are just two things that come to mind.

[lazabby]

While in IGN ON, turn the A/C selector to OFF and the fans will stop turning.
Simple as that.

We purposefully turned the AC on while engine was not running.. We were doing some testing. Strange though that the fans would come on too since the engine was not hot. Is this normal for Deloreans or is it happening because I have the Joe Cool module?

[DCUK Martin]

You need to re-read the above posts.

The fans will come on when you turn the AC on regardless of whether the engine is running or how hot the engine is.

[DMCMW Dave]

We purposefully turned the AC on while engine was not running.. We were doing some testing. Strange though that the fans would come on too since the engine was not hot. Is this normal for Deloreans or is it happening because I have the Joe Cool module?

Normal. The circuit has no idea whether or not the engine us running. As long as the freon pressure is over about 40PSI the compressor will engage (click) and the fans will turn on. And run your battery down.

It has nothing to do with the Joe Cool, any normal DeLorean will do that.

[lazabby]

Normal. The circuit has no idea whether or not the engine us running. As long as the freon pressure is over about 40PSI the compressor will engage (click) and the fans will turn on. And run your battery down.

It has nothing to do with the Joe Cool, any normal DeLorean will do that.

Th authority has spoken! Thanks Dave. One less thing to worry about. Although the AC does cycle too often in my opinion. Probably low on Freon.

[Ron]

Just in case:
If you were "cycling" the AC switch instead of the AC cycling, as in your OP, you are good to go. Otherwise you have a problem that needs attention...

[lazabby]

Just in case:
If you were "cycling" the AC switch instead of the AC cycling, as in your OP, you are good to go. Otherwise you have a problem that needs attention...

This seems to contradict what other are saying, unless I'm misreading your post. We simply had key on (engine not running), turned the AC to "Norm" or "Max" , turn the fan switch to "1" position. The AC compressor would cycle and when it did kick on, the radiator fans also turned on. The radiator fans turned off when the AC compressor turned off.

[dmc6960]

This seems to contradict what other are saying, unless I'm misreading your post. We simply had key on (engine not running), turned the AC to "Norm" or "Max" , turn the fan switch to "1" position. The AC compressor would cycle and when it did kick on, the radiator fans also turned on. The radiator fans turned off when the AC compressor turned off.


No, its still exactly what everyone is saying. Whenever the AC compressor is on, the fans are on.

Now, what IS UNUSUAL is for the AC compressor to automatically cycle off while the engine is not running. The cycling is controlled by a high and low pressure switch. Theoretically the system cannot achieve a high or low enough pressure for this without the compressor turning. How frequently did it happen? What time frame was it on vs off?

Edit: Also what kind of temperatures was this happening in? Also sun or shade?

[lazabby]

No, its still exactly what everyone is saying. Whenever the AC compressor is on, the fans are on.

Now, what IS UNUSUAL is for the AC compressor to automatically cycle off while the engine is not running. The cycling is controlled by a high and low pressure switch. Theoretically the system cannot achieve a high or low enough pressure for this without the compressor turning. How frequently did it happen? What time frame was it on vs off?

Edit: Also what kind of temperatures was this happening in? Also sun or shade?

The AC Compressor would cycle about every 15 seconds or so which I think is too much. It wasn't too hot outside. The car was in the sun though.

[dmc6960]

The AC Compressor would cycle about every 15 seconds or so which I think is too much. It wasn't too hot outside. The car was in the sun though.

15 seconds on then 15 seconds off then?

And if the engine was idling in those same conditions, how frequently would it cycle?

If you happen to have an AC manifold gauge set, you could hook it up and see what the pressure do. Perhaps the equalized but solar heated system did several low pressure cycles due to just the fans running. I'd think its a long shot but my only guess at this point, and the freon level would probably have to be pretty low for that to happen. I can't say I've ever left the compressor engaged without the engine for longer than a minute.

[Ron]

+1 Jim x 2

[lazabby]

15 seconds on then 15 seconds off then?

And if the engine was idling in those same conditions, how frequently would it cycle?

If you happen to have an AC manifold gauge set, you could hook it up and see what the pressure do. Perhaps the equalized but solar heated system did several low pressure cycles due to just the fans running. I'd think its a long shot but my only guess at this point, and the freon level would probably have to be pretty low for that to happen. I can't say I've ever left the compressor engaged without the engine for longer than a minute.

The AC does cycle pretty frequently when the engine is idling.

[DMCMW Dave]

The AC does cycle pretty frequently when the engine is idling.

It should not cycle at all with key on /engine off. The pressure isn't changing.

The cycling period with the engine on depends on a lot of things:
--Ambent Temperature
--Speed setting of the blower
--Max or Normal if the doors are closed (won't really be any different if they doors are open)
--Engine RPM
--and finally, the state of the refrigerant charge.

You can't jump to the conclusion that it's low just based on cycle time. If the blower is set to zero (or even speed 1) on a relatively cool day it will cycle very quickly even if charged properly.

[lazabby]

It should not cycle at all with key on /engine off. The pressure isn't changing.

The cycling period with the engine on depends on a lot of things:
--Ambent Temperature
--Speed setting of the blower
--Max or Normal if the doors are closed (won't really be any different if they doors are open)
--Engine RPM
--and finally, the state of the refrigerant charge.

You can't jump to the conclusion that it's low just based on cycle time. If the blower is set to zero (or even speed 1) on a relatively cool day it will cycle very quickly even if charged properly.

Ok Now I'm confused. Message 8 indicates that the fans will turn on and off with the AC condensor turning on and off. Remember I'm talking about radiator fans. The engine is not on. The key is on the "on" position. The AC switch is turned on. On my car, the AC compressor kicks on and off every few seconds. When it kicks on, the radiator fans kick on. I'm getting conflicting answers here. Which is it?

[Bitsyncmaster]

Without the engine running your AC compressor should not be turning on and off unless your switching the mode switch to do it.

If it is turning on and off then you need to find out why. Maybe someone installed a circuit breaker in that circuit and it is tripping. Stock setup has no breaker.

[Ron]

+1
=======

When the key is ON, the Mode switch is enabled. Then, if the Mode Switch is set to any AC mode, power is sent to the Low Pressure Switch. If the refrigerant charge is correct (and the ambient temp isn't extremely cold), it will send power on to the Compressor Clutch AND the Coolant Fan Relay -- They are tied together (with a Diode on the Relay side). (Note this Relay can also be energized by the Otterstat independently, through its own Diode, which keeps the Otterstat from turning on the Compressor Clutch too). The Coolant Fan Relay feeds a Thermal Trip Breaker, which feeds the Coolant Fans.
So, what should happen with the Engine OFF and Key ON is, the Coolant Fans AND Compressor Clutch should be ON and STAY ON.

The rest of the story-
And if the Mode Switch is not set to an AC mode, the Compressor Clutch will not be energized, and, the Coolant Fans would come ON depending upon the temp at the Otterstat (which could cause the Coolant Fans to come on a few times at most, but not likely, but it never causes the Compressor Clutch to energize).

Now, if the Engine is ON, everything is the same as above except the Low Pressure Switch (and thus the Coolant Fans and Compressor Clutch) may cycle ON and OFF, depending on the effect the things Dave S mentioned above have on the low side pressure... slow, fast, or constantly ON can be normal.

What "work" were you doing around the time you noticed this? Something to do with wiring, the Diodes, or Joe Cool?

[TTait]

If it is turning on and off then you need to find out why. Maybe someone installed a circuit breaker in that circuit and it is tripping. Stock setup has no breaker.

My thought as well... Check for a breaker.

Think of it this way - there are three things that can turn on the fans under normal circumstances:


Key on and engine off - turn on the A/C
Key on and engine running - but cool - turn on the A/C
Key on and the engine is warm/hot - regardless of AC setting or if engine is running


Once the fans are on, they will turn off for only 3 reasons:

Turn the key off
The engine/coolant cools to the point the otterstat switch turns off, and the AC is not calling for cooling because it is either off or the pressure switch is tripped
The engine is running but is not hot AND the AC compressor has run long enough to trigger the pressure switch shutting off both the compressor and the fan. Note that this is impossible if the engine is not running and turning the compressor

[lazabby]

I think the real question is not whether the fans should be turnng on and off with the AC when the ignition is on and engine is off, but whether the A/C should be cycling, is that correct? The concensus is that the fans should turn on when the A/C compressor kicks in whether the engine is running or not. The real question is whether the A/C should be cycling while the enegine is off. Is that correct? If it should not be cycling, then I need to look into it. Please let me know if I am misunderstanding the issue here.

[DMCMW Dave]

I think the real question is not whether the fans should be turnng on and off with the AC when the ignition is on and engine is off, but whether the A/C should be cycling, is that correct? The concensus is that the fans should turn on when the A/C compressor kicks in whether the engine is running or not. The real question is whether the A/C should be cycling while the enegine is off. Is that correct? If it should not be cycling, then I need to look into it. Please let me know if I am misunderstanding the issue here.

You are correct. None of us can think of any good reason for the compressor to cycle with the engine not running. I can't even think of any bad reasons. The compressor itself is powered from the aux relay, through Fuse #10, via the mode switch and the low/high pressure switches. No breakers unless someone has changed things.

Just out of curiosity, what happens with the engine running. Does it make cold air? How fast does it cycle with the engine at idle, blower on full speed, at, say 70F in the room?

[lazabby]

You are correct. None of us can think of any good reason for the compressor to cycle with the engine not running. I can't even think of any bad reasons. The compressor itself is powered from the aux relay, through Fuse #10, via the mode switch and the low/high pressure switches. No breakers unless someone has changed things.

Just out of curiosity, what happens with the engine running. Does it make cold air? How fast does it cycle with the engine at idle, blower on full speed, at, say 70F in the room?

I'll try and trace the circuit to see if anything unusual has been installed on it. The AC does blow cold air but it seems to cycles about every 15-20 if I remember correctly. It's been a few months since I've run it and it's recently beed down for some changes doen to it. I'll be driving it in the next few days and I can turn on the AC to see how often it cycles.

[Ron]

...
I'll be driving it in the next few days and I can turn on the AC to see how often it cycles.

Again, when you are driving (or engine running) you have to at least know that the refrigerant charge is correct and the ambient temperature, otherwise how often it cycles is all but meaningless....

Stab in the dark:
Pull fuse #10 then #5 to see which is feeding "the problem".
If it's #10, look for an added thermal breaker (or mis-wiring), as suggested.
If it's #5, check for a shorted diode off of the Otterstat.
Otherwise, I'd try temporarily removing the Joe Cool and wire it stock....

[Bitsyncmaster]

Here is a thought. When the compressor and fans kick on, the battery voltage drops after some time and then the Aux relay drops out. After the battery voltage recovers, the Aux relay kicks in again.

[Ron]

I was going to suggest that yesterday...but it didn't seem likely that it would do that AND have enough power to run the fans at 15 second intervals??
Definitely worth checking tho!

[Bitsyncmaster]

I was going to suggest that yesterday...but it didn't seem likely that it would do that AND have enough power to run the fans at 15 second intervals??
Definitely worth checking tho!

It would have to be a faulty AUX relay which is highly unlikely. It still sounds like someone put a breaker in the fan cicuit that's tripping.

[Ron]

It would have to be a faulty AUX relay which is highly unlikely. It still sounds like someone put a breaker in the fan cicuit that's tripping.
+1 !

...seeing if the panel light lights cycled too would probably be the easiest way to check the AUX relay.

[lazabby]

I'm still trying to figure out whether my AC is running normally. As I said in a previous post, if I have my key on with the engine NOT running the AC will cycle. Someone indicated that this is not normal. Now for the strange thing - if my fans are on when the engine is running and I shut off the engine, my fans will continue to run for a few seconds. This doesn't appear to be normal. I am suspecting the Joe Cool module. I plan to run some tests by pulling the Joe Cool and putting in the stock system. Since Joe Cool commands relay plugs #6 and #7, I'll have to put something in those relay spots. I have the three wire (prong) fused thingamajig for relay #7 and I'm still trying to confirm which wires go where. Can the standard relay go into relay plug #6?

[dmc6960]

my fans will continue to run for a few seconds. This doesn't appear to be normal. I am suspecting the Joe Cool module.

It is normal, this is what the Joe Cool is supposed to do. No need to test this.

When your AC "cycles" with the engine off, does the compressor clutch engage and disengage? Go back and actually watch it.

[Spittybug]

Shannon, you fans didn't just continue to run, I recall them actually starting up without warning when the engine was off and the key in "aux" not "run". Now, I may be mistaken about the key position, but I'm pretty damned sure on the starting up (without engine running). THAT's what I thought was odd.

[lazabby]

Shannon, you fans didn't just continue to run, I recall them actually starting up without warning when the engine was off and the key in "aux" not "run". Now, I may be mistaken about the key position, but I'm pretty damned sure on the starting up (without engine running). THAT's what I thought was odd.

From what I understand, the fans will always come on when the AC cycles. If we had the key on (engine not running) and the AC switch on, then the AC would have been cycling and the fans would have been going on and off with the AC.

Still trying to determine the RPM drop when we turned on the AC. That's why I was asking about Joe Cool. I've been cleaning grounds, fuses, relays, etc. I'm wondering if low freon may be causing the compressor to work harder? Still wouldn't explain the RPM drop. I still need to check/clean the major grounds. I'm thinking about doing a set up similar to Hervey where the battery ground goes to the trailing arm nut on the plate and then to the transmission.

[jawn101]

From what I understand, the fans will always come on when the AC cycles. If we had the key on (engine not running) and the AC switch on, then the AC would have been cycling and the fans would have been going on and off with the AC.

Still trying to determine the RPM drop when we turned on the AC. That's why I was asking about Joe Cool. I've been cleaning grounds, fuses, relays, etc. I'm wondering if low freon may be causing the compressor to work harder? Still wouldn't explain the RPM drop. I still need to check/clean the major grounds. I'm thinking about doing a set up similar to Hervey where the battery ground goes to the trailing arm nut on the plate and then to the transmission.

Whether you get the cables from Hervey or not (mine are) that transmission ground setup is amazing. I gained almost 2 full volts immediately and the starter spins much more freely.

[Spittybug]

From what I understand, the fans will always come on when the AC cycles. If we had the key on (engine not running) and the AC switch on, then the AC would have been cycling and the fans would have been going on and off with the AC.

If engine isn't running, the AC shouldn't cycle. Cycling is a function of pressures in the system isn't it? No compressor running...................

[Bitsyncmaster]

If engine isn't running, the AC shouldn't cycle. Cycling is a function of pressures in the system isn't it? No compressor running...................

Correct. The pressure if above 45 PSI the compressor and fans will got on and stay on. If below 30 PSI the compressor and fans will not turn on ever. In the winter I've seen the pressure so low the fans don't turn on.

[lazabby]

I assume we've established that with the key on and the engine not running, that if one turns on the AC then the fans will kick on when the AC kicks on. The question is should the AC cycle? And the conclusion is that it should not cycle. Since mine does cycle, then what is causing the cycling? Low freon?

[Bitsyncmaster]

I assume we've established that with the key on and the engine not running, that if one turns on the AC then the fans will kick on when the AC kicks on. The question is should the AC cycle? And the conclusion is that it should not cycle. Since mine does cycle, then what is causing the cycling? Low freon?

No a low or high freon charge will not make the AC cycle without the engine running. You are going to need to use a volt meter to find what is happening. Have you tried replacing the fan relay yet?

[lazabby]

No a low or high freon charge will not make the AC cycle without the engine running. You are going to need to use a volt meter to find what is happening. Have you tried replacing the fan relay yet?

I haven't replaced the relays yet. I have the three prong fused wires for the #7 relay socket. Can a regular relay go into relay socket #6?

[Bitsyncmaster]

I haven't replaced the relays yet. I have the three prong fused wires for the #7 relay socket. Can a regular relay go into relay socket #6?

Yes. You can swap it with another relay to test it.

[Ron]

Can anyone who is 110% certain tell me if the Joe Cool requires any wiring or other alterations, or is it simply pull two relays and plug it in?

[dmc6960]

I can. Because while at DCS someone I was with wanted to buy one, but Dave Swingle cautioned first to make sure the wiring for the fan circuit had NOT been modified. I checked his car and indeed it had. On this particular car it was not a bad modification, but it would have caused the Joe Cool to not work.

[82DMC12]

I just put a Joe Cool in my car. Basically if your fans work correctly with the three plug jumper, take the jumper out, plug Joe Cool in, and it should work correctly. Any other "mods" and all bets are off!

[DMCMW Dave]

Yes, for the fan controller to work (not just this one, but even the old FanZilla or the other plug-in units) the wiring in the car must be factory stock.

The most common mod is that some people have eliminated the fan fail socket wiring and just connected the fan wiring together underneath (with or without fuses). If this has happend the Fan Controller will not function. The fans will not work with the Controller but will work if you put the relay back in the second socket.

The "tell" on this is if your car has nothing plugged in to the far left/blue socket, the modification has been done. If there is a blue fan fail module there, I'd suggest you unplug it and see if the fans still work. If they do, someone did the mod and left the fan fail module in place for appearance.

[lazabby]

Just so that everyone is clear on it, Joe cool replaces the two relays that go into relay sockets #6 and #7. As I understand it, #6 controls the cooling fans and#7 controls the fan fail.

[DMCMW Dave]

Just so that everyone is clear on it, Joe cool replaces the two relays that go into relay sockets #6 and #7. As I understand it, #6 controls the cooling fans and#7 controls the fan fail.

Not exactly. It changes the way it works completely.


In the original setup the relay in Socket 6 is powered from the battery and triggered by the otterstat or A/C. The relay feeds the breaker, which feeds the blue module. The blue module feeds (the outer pins) the two fans and has a circuit to turn on the light if either fan goes open.


In the Sequential Controller, the control box is powered from Socket #6 and is still triggered by the otterstat and A/C. The circuit in the box powers the fans directly through socket #7, and also can light the "fan fail" light which is the center pin of socket #7. Inside the box are two relays, as separate one for each fan, as well as the time delay circuits. The circuit breaker is bypassed.