Fire"Dutch"Bird

iTrader: (1)

Today I noticed that the left fan ( driversside) of my car is not working, the right one is working fine.
When I jump terminals A&B on the ALDL neither one of the fans are working, I remember at least one did when jumping those terminals, I suppose the left one.
Where should I look?
Is the relay for the fans at the driverside firewall?
There are three relays there, two oval shaped ( part# 14089936) and one square ( part # 10094701).
I looked at the fuses, but they seem OK.
With just one fan, car is overheating at idle....!

Zepher

iTrader: (1)

Car shouldn't overheat with the 1 fan running, so you have some other issue causing it, unless the 1 fan is the passenger side fan which only comes on when the car reaches overheating temp, or the AC is turned on and working.

On my 88 Formula, the relays for the fans are near the air cleaner, 1 on the fender and 1 next to the radiator.

left fan is the drivers side fan and right fan is passenger side fan. Which fan is not working?

The computer controls the left fan and the sensor is on the front of the intake under the throttlebody, it is a small 2 prong sensor.

Fire"Dutch"Bird

iTrader: (1)

Driver side fan is not working.

Fire"Dutch"Bird

iTrader: (1)

When I jump terminals A&B at the ALDL, this bypasses the sensor you mention, right?

Zepher

iTrader: (1)

plug 12 volts to the fan and see if it spins, or you can turn on the ignition and jumper the relay to ground, should be the green wire on the relays by the air box.

Zepher

iTrader: (1)

it should, so it could be a relay, fuse-able link (I think there may be one) or the fan motor itself.

ASE doc

I beleive the left fan is the one which is controlled by the ECM. As Zepher said, the ECM gets its coolant temp info from the two wire sensor under the TB. You can test the relay and fan motor by jumping the small green/white wire to ground. You can use a test lead and a paper clip to back probe the connector. With that terminal of the relay grounded, the fan should run. If not, listen for the relay to click. If it clicks, then with the relay on, check for power at the fan connector If no power there, check for power at the relay.

Suspect a bad fan motor. The relays can fail but not often. If the relay and fan test okay, check the green/white wire from the ECM. Check coolant temp sensor/circuit. Coolant temp sensor also affects fuel mixture and timing. If CTS is bad engine will run either very rich or very lean, depending on whether sensor/circuit is open or shorted.

Fire"Dutch"Bird

iTrader: (1)

So if I ground the green wire at either relay, one of the fans should spin?
Ignition on, I suppose?

Zepher

iTrader: (1)

yes, ignition needs to be on.

Fire"Dutch"Bird

iTrader: (1)

OK, thanks for that.
As it's almost midnight overhere, I will test it tomorrow evening.
Just a question, I've been trying to adjust my Granatelli adjustable MAF sensor all evening, have reset the ECM many times tonight, could this have affect the fan, or are they not related at all ?
(As this Granatelli MAF is a PITA to work correct, I might go back to the original Bosch MAF.....but I guess that's another story)

Zepher

iTrader: (1)

should be independent and not conflict at all.

Reid Fleming

iTrader: (2)

Read my signature.

Fire"Dutch"Bird

iTrader: (1)

I have grounded the green/white wires on both relays, but nothing happens...!
No fan comes on.
But at idle, at the correct temp. the passengersside fan comes on....!

Zepher

iTrader: (1)

You don't hear the relay click when you ground the green wire?

I have my green wires wired up to a switch and then grounded since my fans wouldn't come on when I bought the car 7 years ago. They started working on their own 5 years ago when I pulled the ECM down, so maybe I had a loose wire at the harness.

This where my relays are on my 88, probably the same place as yours, right?

Fire"Dutch"Bird

iTrader: (1)

Correct, that's the place.
I'll try again tomorrow, I pulled the wireharness out of the relay, and grounded the green wire, but I understand now, I have to leave the harness in the relay...!
How do I ground the green/white stripe wire without cutting it?

ASE doc

Hello Reid fleming, That is the best cooling fan diag sequence. BTW, that book is the Helms/GM factory service manual.

Zepher

iTrader: (1)

you can use a paperclip to get up into the connector from the bottom or you can carefully use a pair of wire strippers to cut the shielding and pull it down a little, or use a sharp nail or pin and push it into the shielding and use a wire on ground and touch the pin or nail.

Fire"Dutch"Bird

iTrader: (1)

OK, I'll try that.

Fire"Dutch"Bird

iTrader: (1)

I grounded both relays, (one at a time) like you told me, the passengers side fan works, the drivers side fan doesn't, the relay is clicking.
What do I do now..?

Zepher

iTrader: (1)

plug the drivers side connector into the pass side fan and see if it works, this will verify that the wiring is good to the drivers side connector, unless you have a meter handy, then you can just check to see if you have 12v at the drivers side connector when you activate the relay.

If you have power there, then replace the fan motor.

Fire"Dutch"Bird

iTrader: (1)

Zepher,
Are the left and right fanmotor the same?
Can you maybe confirm the following GM part number: 22074969.
I found this in a (non complete) GM parts catalog.
If the number is correct, I will try to get a new one overhere, I hope it's still available...??

Zepher

iTrader: (1)

Yep, both fan motors are the same.

Fire"Dutch"Bird

iTrader: (1)

GM doesn't stock this fanmotor anymore.
I found a direct replacement at a large USA carparts store overhere, they are going to order it for me, hope to get it somewere next week.

Fire"Dutch"Bird

iTrader: (1)

Well, it wasn't a replacement brand, but original Delco...!
But instead of part # 22074969, I got part # 22137319 ( 88890701), it looks the same, so I hope it works the same.
One thing, on the instruction sheet in the box, they mention two options: "thin drive plate" and "thick drive plate", as far as I can tell, the new motor has the thick drive plate, is this OK?
Hope to find the time this weekend to change the motors.

Fire"Dutch"Bird

iTrader: (1)

No luck today....
The relay is clicking but the new motor isn't working....now what...??

Fire"Dutch"Bird

iTrader: (1)

The Reid Flemming scheme shows a "fusible link" for the drivers side fan.
Where exactly is it, and can it cause my fan not to work?

Fire"Dutch"Bird

iTrader: (1)

Well, the fan still doesn't work....!
But it's winter right now, so the car is in storage.
Hope to cure it next season.

Fire"Dutch"Bird

iTrader: (1)

6 years later, car was in storage all the time, but I finally have the left fan working again today....!!
I had noticed a bad connector at the fuel relay, so I replaced it today, together with a new Airtex relay.
Fan is working fine, also maf burn off is working again, so no more code 36 light...!
I assume that a lot of systems are grounded by the same wires at some point, and when a ground goes bad for some reason, all kind of weird problems occur...