I have a 1989 2.0L that overheated in traffic. The fan was not working. I looked at it quickly the other day, and hope to look at it further today/tomorrow. I could use some troubleshooting tips....

1) What/where is the protection (fuse, link, etc.) for the fan power, in case something took it out?

2) I assume the relay is the one mounted under a cover on the firewall, in front of the driver. I am not 100% positive because the wiring is different from what appears in diagram in my Haynes book (wiring colors, my relay has 5 wires attached while the book only shows 4). Of course, the diagram in the book only said that it is "typical" for my year range.

3) When I pulled the relay off, there was black gunk all over it (on the spade connectors, etc). Is this normal? Perhaps this is an ancient compound (dielectric, waterproofing, anti-corrosion, etc.) from the factory?

4) I cannot test the fan by turning on the A/C, the A/C doesn't work.

5) I don't really have anything to connect the fan directly to the battery with. I am guessing that I would ideally need alligator clips to probes, with decent-sized wiring to handle the current.


Thanks!

The relay is right behind the battery, the one under the cover by the firewall is for the fuel pump. The black goo is a sealant to protect the terminals from moisture. With the ignition on and the engine off, if you jump the diagnostic terminals on the ADL connector under the dash, the computer will ground the relay and turn the fan on. You should hear the relay click in when you do this, if not it maybe just the relay, or the ecm. The fan goes on, it is possible the coolant sensor is out of calibration.

FrankD wrote:The relay is right behind the battery, the one under the cover by the firewall is for the fuel pump.

If true, then I got them mixed up. I always ASSUMED fender one was for fuel pump, for some reason. I should have checked the wiring to both and verified/figured it out. Inexcusable sloppiness on my part.

FrankD wrote:The black goo is a sealant to protect the terminals from moisture.

I figured as much.

FrankD wrote: With the ignition on and the engine off, if you jump the diagnostic terminals on the ADL connector under the dash, the computer will ground the relay and turn the fan on.

Holy smokes, I forgot all about this! Yes, I remember the fan kicking on when I have done this.

FrankD wrote:You should hear the relay click in when you do this, if not it maybe just the relay, or the ecm. The fan goes on, it is possible the coolant sensor is out of calibration.

I assume it is the motor or relay, but you never know, particularly on a 26yo car.

I will run the ECM diagnostic mode, check for power at the fan, and take it from there.


Thanks!

Someone on the Pontiac forums grounded the green wire to the relay ( computer signal wire) to get his running,

I eliminated the whole crap all together , wired it to the ignition on so it runs all time. Added
a led letting me know its spinning = piece of mind that my head gasket wont blow.

Doug in P.R.


92 Pontiac Sunbird LE, 2.0, AT, Red / Black with Grey 155K miles. Hurricane Maria Survivor ! ( It takes a licking and keeps on ticking ! ).....in Salinas, Puerto Rico!

baron5867 wrote:If true, then I got them mixed up. I always ASSUMED fender one was for fuel pump, for some reason. I should have checked the wiring to both and verified/figured it out. Inexcusable sloppiness on my part.

OK, a little hard on myself... I did, for some reason think that that relay behind the battery was for the fuel pump, but I DID look at the online repair info on Autozone's website, and they did say that the cooling fan relay was located "Under hood, driver side, rear side of strut tower, driver side of brake master cylinder, mounted on upper firewall". Still, I should have known something was up when the wiring didn't match.

In any case, I pulled the relay and checked for voltage at the two terminals which power the fan. There was 12+ volts. I connected ("shorted") those two terminals, and the fan started.

I picked up a relay from an '88 Z24 at the JY, and plugged it in. The fan still did not work. It is possible that the JY relay is gone as well. God knows how long that car was there or when the last time that relay was activated.

I checked for voltage across the relay connector's two control (PCM) terminals, and I got 1.8 volts. Anyone know if this is good? Does anyone know what the specified voltage is for the control terminals (for the solenoid) on the relay, to do some type of bench test? I prefer to verify the relay is the problem before buying a new one. Thanks.

92Sunbird PuertoRico wrote: I eliminated the whole crap all together , wired it to the ignition on so it runs all time. Added
a led letting me know its spinning = piece of mind that my head gasket wont blow.

I don't have any objections to the original design, provided it is working correctly.

I just dont like the original system thats all, I think the system on the early XBody cars ( Citation) was the better system. ( thermo switch)

When you start asking a computer to turn please on your fan , your asking for trouble. And you never know till its too late as your head cooks.

Just my 2 cents.............. To each his own. ( I dont even run a thermostat in mine down here)

Doug in P.R.


92 Pontiac Sunbird LE, 2.0, AT, Red / Black with Grey 155K miles. Hurricane Maria Survivor ! ( It takes a licking and keeps on ticking ! ).....in Salinas, Puerto Rico!

92Sunbird PuertoRico wrote:I just dont like the original system thats all, I think the system on the early XBody cars ( Citation) was the better system. ( thermo switch)

I've never had a problem with a cooling fan until now. And that includes an 88 Cavalier that I bought with 141k miles and put another 200k on. My guess right now is that relay has failed due to age and the lack of use (as might well be the case with the JY relay that I tried.)

92Sunbird PuertoRico wrote:When you start asking a computer to turn please on your fan , your asking for trouble. And you never know till its too late as your head cooks.

The computer is not going to be a problem. The computer just monitors inputs, and sends outputs. It ain't going to "forget". Problems occur with the input and output devices and routes.

Problems with heads only occur with extended or repeated overheats on these cars, in my experience.

Even if you rig the fan to be always on, the fan motor itself can fail (more so when you are running it full-time! ).

92Sunbird PuertoRico wrote:Just my 2 cents.............. To each his own. ( I dont even run a thermostat in mine down here)

Running a car with a fan always on (and/or without a thermostat) is not a good idea in most of the country, at least not year-round. BUt yes, to each his own.

ECM CONTROLS THE GROUND SIDE ON/OFF ,12VOLT SHOULD be at the control RELAY sorry about the caps