stupid fans!!!!

[TheCrazyDSM'r]

My problem is pretty wierd if you ask me. I have installed aftermarket fans. Well I wired them into a power supply. but when you remove the keys and turn off the car, the crazy SOB doesn't turn off( the whole car that is) but about 5 seconds later the car turns off. You can listen to the fans start slowwing then the car turns off. I don't really now how to discribe the problem.

 

[BUCK]

I'm not so sure this is a bad thing...

 

[GTM]

Originally posted by TheCrazyDSM'r
My problem is pretty wierd if you ask me. I have installed aftermarket fans. Well I wired them into a power supply. but when you remove the keys and turn off the car, the crazy SOB doesn't turn off( the whole car that is) but about 5 seconds later the car turns off. You can listen to the fans start slowwing then the car turns off. I don't really now how to discribe the problem.

It's sounding like some part of the ign circuit is finding it's way to ground through the fans. When the key is on and the fans are on all is well. Turning the key off removes the main power to the fans but the ign is still making a path through the fans to ground.

To further complicate this it may be the ign is turning off but as the fans are slowing down they become generators and feeding back into the ign circuit and holding a relay or power transistor in the completed circuit.

Now if that's not enough some fan circuits will continue to run until a preset event happens, e.g. a timed cycle, or temp range is reached.

You could make sure the dash A/C and fan switches are off before switching the key off. An aftermarket radio or power antenna wired incorrectly. After that you are going to go have to go over every connection you made with the Mfg wiring diagram then call them. Unless someone here has installed the same "kit"; I in all probability; can't sort this out without seeing the circuit diagram and how you hooked it up. That's _my_ opinion... which is about 2¢.

Cheers,
GTM

 

[laserblue]

You wrote "fans" - plural. Did you wire both fans together? If you used only one 12v source, and grounded the fans, then there is no way that any other circuit could be affected. If you weird wired the fans into multiple 12 supplies, then strange electrical stuff could happen, like the 12v ignition circuit could jump thru the fan motors to another circuit, and then turning the key off may not stop the ignition voltage.... so the car runs. Of course you could have made a wiring mistake also.
Like said above... it's difficult to diagnose without knowing just what you connected where!! Can you explain or supply a diagram of what you did?

 

[TheCrazyDSM'r]

I have both of the fans wired together. I have them getting there power supply straight from the fan relay. I have also tried other spots but I come up with the same result. The ground is grouned to where the batter grounds out.

 

[GTM]

Originally posted by TheCrazyDSM'r
I have both of the fans wired together. I have them getting there power supply straight from the fan relay. I have also tried other spots but I come up with the same result. The ground is grouned to where the batter grounds out.

Ah nomenclature and logic prevail. You had me thinking this came with an isolated "power supply" which performed some trick functions.

Help us out with more info, what was the reason for replacing the fans? What did you _want_ them to do? How many amps does each draw? What do you mean when you say you tried "other spots"?

Did you change or add anything else, move relays around, add other switches?

I'd suggest you check your relay diagram to make sure you got the _proper_ relay and terminal. I'd also make sure you wired the fans in parallel and not in series.

Any other anomolies or changes to other item"s actions since you did the job?

I've just got this gut feeling you tapped into a floating ground or the relay ground rather than the power out from the fan relay.

It's not too hard to just add a manual overide switch if you are just trying to buy yourself some extra cooling cushion.

Cheers,
GTM

 

[TheCrazyDSM'r]

I had to get the fans because I got a bigger radiator. My lucky day.... I wired in the fans to start once the car turns on because I don't want to worry about cooling problems on the hotter days. I also wanted it though that the fans turn off with the car and that I wouldn't have to worry about turning them on or off. Sometime I forget and I don't want to worry about them. When I said other spots, meant other relays. I like tried the A/C relay and so forth. All showed me the same result. I'm thinking on just buying the fan install kit from napa. I'm not sure I really want to figure out what is wrong first. Also, the only other then that was change resently was the alternator. I got it from Advance Auto Zone.

 

[BUCK]

I wouldn't have cut out the thermo-switches if I were you but I understand if your new radiator doesn't have the fittings although there may be a spare boss in your thermostat housing - I always thought it would be best with these cars if at least one of the fans stayed on low speed & cycled - even with the ignition off - until the water temp told the fan thermo-switch to stay off (like a Honda does - I know - I know, but they do have some good engineers over there...) That way the spike in water temps that ALL cars see when you cut them off could be mitigated. The fan cycles a few times just until the temps drop - the water circulates via convection until the thermostat closes - Lord knows these things see a BIGGER spike in temps when you cut them off than most any car. That system to me would be far better than even a Turbo timer. I would guess that powering one side of the radiator fan relay coil all the time might do the above - looking at the scematic it looks like the Blue Wire with a Black stripe going into the relay connector from the Ignition - but I am severely electrically challenged - I'm still gonna try this one day with a FUSED source & LOTS OF FUSES.

YOU are in a great position to help us all figure out how to do this as you are in the middle of the entire fan control system anyway...

 

[GTM]

Originally posted by TheCrazyDSM'r
...

I wired in the fans to start once the car turns on because I don't want to worry about cooling problems on the hotter days. I also wanted it though that the fans turn off with the car and that I wouldn't have to worry about turning them on or off.
...
I'm thinking on just buying the fan install kit from napa. I'm not sure I really want to figure out what is wrong first. Also, the only other then that was change resently was the alternator. I got it from Advance Auto Zone.

That shouldn't be a problem, you need to wire a relay from the battery through the relay to the fans. From a circuit which gets energized with the key on you wire to the relay contro then to ground. When the key is on the fans are on, key in accessory position fans are off. The problem will be finding a relay which can handle both fans (10 amp each minimum=20 amp relay) However finding a quality relay which will handle start loads means at least 30 amp to run both fans. Alternately you could have 2 15-20 amp relays each dedicated to 1 fan only. Should one system fail you have at least 1 fan running. You will need to put a fuse or circuit breaker in between the battery and the relay power side.

That's a simple installation, want it a bit more advanced wire the relay into the circuit which is only energized when you have oil pressure or alternator output.

The problem with having them on all the time is when you or a mechanic is working on the car and needs the switch on but the car not running. They will find something to unplug or CUT. That's why I recommend using the existing system and then having a toggle switch which can only come on when the ign switch is on but you can't forget to turn it off when pulling the key. Again this comes through a fused relay from the battery but the relay control power comes from an ign switch ON position source.

Question, when you unplug the fans does the engine shut off normal?

Cheers,
GTM

 

[BUCK]

His car has those relays already - if he wants to cut the thermo switches out of the fan control circuit for some reason then just jump the thermo switch out - The stock set up has the fan relays powered only when the ignition is on - When the HVAC button is depressed the AC fan runs regardless of engine temp so there is another option for him. I'm no electrician but somebody needs a schematic & it aint me.

 

[TheCrazyDSM'r]

Thanks everyone for all the help. I did figure out the problem yesterday. About 3 hours after my last post. I just thought would be a good idea to post the problems that I found with the fans and the relay.

Ok, 1st off the relays for the fan are controled by our ignition relay/switch. This is why the fans are suppose to turn on and off with the key being in the on or off position. This is the normal operation of the fan system.

2nd, When I had added the fans I pluged them into the normal fan relay. This way the fans would come on when you put the key and turn the ignition switch to the "on' position. However, I was seeing the problem that the can wouldn't turn off if the keys where removed ( and the turbo timer was off). The car would turn off a couple seconds later as the fans seemed to slow down.

3rd, We the fans have motors in them. They are electric motors and all motors can create there own electric current.

4th, So while these fans are on they were creating an counter-electromotive force. This force was actually just enough power to cause the relays to stay "on", or really in the closed position. It was also enough to cause the ignition relay to stay closed as well.

5th, So the car would finally turn off once the fans stopped producing enough counter-electromotive force to keep the relays closed. ( Once the fans' motors slowed and current wasn't as strong.) The relays would then open and then the car would turn off.

6th, My great solution to the problem at hand was rewire the relay, I set it so that the counter-electromotive force was sent out of the line back to the battery. This fixed the "stupid fans" problem. Now I can go drive my car and listen to it purr for alittle bit before I have go work.



So if anyone wants a better explaination please don't hesitate to ask me.

 

[laserblue]

Question about #4:
Where did you connect your fans. If you connected them to the COIL side of the relay [very wrong] when that would explain why the fan motor [acting as a generator] would keep the relay coils energized for a bit.
Also since the fans continue to rotate in the same direction after you key-off the power, then the current that they generate will be reverse polarity when the motors are acting like generators. That could do BAD-BAD to other stuff in the circuitry.
About relays:
They have a couple of important reasons for being there. First, they can take a small amperage circuit and control a very high-draw circuit, thus putting little strain on the controlling circuitry. Second, they isolate the device [at the contact terminals] from the rest of the electrical circuitry, so BAD things cannot happen - like an engine that continues to run, for instance........ Hummmmmm, sound familiar? OR toasting the ignition switch.. or even worse - the ECU!
Anyway, if whatever you finally did works, and you're not stressing out any wiring or components that are not meant to handle huge current, then GREAT GOING!!
If you write back in a week and say that the steering column has gone up in smoke then---

 

[TheCrazyDSM'r]

Right the relays is still they, but all it is doing is just sending that extra current away from the relay so that is doesn't keep the relay closed once the ignition is turned off. It isn't that the relay is completely rewired there is just a spot to allow the current the fans motors create to feed off. There is something like this in the factory fan wiring, but I'm not using the factory wiring. So I had to make something similar. I hope that made sense. I'm not to good at explain what I did, yet.

 

[GTM]

Originally posted by laserblue

...
Also since the fans continue to rotate in the same direction after you key-off the power, then the current that they generate will be reverse polarity when the motors are acting like generators.
...

Hmmm, been a long time since I did this. Laserblue if you have a spare fan motor chuck the shaft up in a 1/4" 110v drill (not a battery drill they don't turn fast enough) and check the output polarity. I'm thinking that the output will in fact maintain polarity on the over-run. Should you be right then I would think the motor would actually decay at a faster rate. All I've got are some tiny motors taken from CD drives some of which are intended to reverse.

You can do it with the blade on by wraping in a shop rag and chucked in a vice so you don't crush the housing. Just watch your fingers when the test probes fall off and you reach around... whack!!

I believe some of electric cars utilize this output with drop out relays and shunting to subordinate or lesser potential batteries for recharge on decelerating.

Cheers,
GTM

 

[GTM]

Originally posted by TheCrazyDSM'r
Thanks everyone for all the help.
5th,...
( Once the fans' motors slowed and current wasn't as strong.) The relays would then open and then the car would turn off.
...
So if anyone wants a better explaination please don't hesitate to ask me.

Exactly so, that's what I thought you had done and now fixed.

Another case marked solved!

Now you got that done, go take a look at the "bulb check" circuit and your hazard lights... there is gonna be a test. You got 5 minutes to comprehend cuz we aint gonna pay you for diagnostic time so the rest is on your nickle. No wonder mechanics have become parts changers and I bailed out of the industry. I got tired of fighting the DSMs (district service manager) who didn't have a clue what a conditional floating ground was.

Cheers,
GTM