How do I diagnose radiator fan problem?

[eDiTicX]

So far here is what I've got. The relays are all working. I took the relays out, gave them 12v charge and used a multimeter to test them. All worked fine. So then, I took the fans and gave them a hardwire charge and both the passenger and driver fans spun. Now my question is, is there a way to check the ecu to make sure it is not the problem? And is there anything else I can do for a diagnostic test? Also grounded the thermometer to check it and it worked. And for clarifications, its a 420a turbo 2g.

 

[Turboturd]

So what exactly is the problem your having? I know you have tested things, but you never said if the fan isn't kicking on when it should or the car is overheating, or whatever.

 

[GDNF2ET]

With the ignition on, pressing the AC button will immediately turn on one fan...The black connector that connects the harness to the fans is known for developing a short..I bypassed this connector and hard wired it..I hope this helps..

 

[eDiTicX]

Yes the fans are not kicking on the the car warms up, and they are not kicking on when the car starts to overheat on the freeway. @ the second response, I will hardwire if I absolutely have to, but I would much rather prefer to get it working correctly with the engine. If its the small black connector piece on the wore harness, couldn't I just get a new plastic piece to replace?

 

[bryanwheat]

Overheating on the freeway doesn't have much to do with the fan. The volume of air being moved thru the radiator when the car is moving is much higher than the fan can produce. The fan is only effective at low speeds and idle. You could take both fans out and as long as you are moving so fast it will stay cool. Sounds more like you have a problem elsewhere.

 

[Jmmahon]

As he said the fans are only need for low speed and idle, so I would check for restrictions in front of the radiator or in the cooling system. The PCM would be the last thing I would check, I would test for continuity or voltage on the wires between the PCM and the relay and the relay in the fan. If there is no voltage going out of the PCM it is probably a BUS in the PCM, if there is voltage out of the PCM but not before the relay then there is probably a break in the wire. I would check that before the PCM.

 

[pacn91]

If you can verify that you are getting source voltage, then rememeber to check ground as well. if the plug is bad then you can always cut and splice in a new set of matching connectors. (male/female speaker connectors, weather pak, trailer harness, used/new o.e. connectors)

 

[PlanZero]

My old fan stopped working when it was supposed to, so I took it out and cleaned the motor and it worked for awhile, then crapped out completely. Wound up getting a new one from the junkyard for $6. Also, have you changed your ect sensor lately? When I changed mine, my fan wouldn't shut off. Had to replace the connector as well, now it's fine.

 

[eDiTicX]

Thanks for the responses everyone and sorry for such a late response. I've been super busy.

So I did test the fans with the snowflake button (A/C haha) and it DOES make the fans kick on. So would the problem lie somewhere with a sensor? I've been having problems with the coolant overflow keep filling also so I just went and bought a new thermostat and new radiator cap in hopes to solve that. I don't think it will solve the fan problem though.

 

[talonesi95t]

I've been having problems with the coolant overflow keep filling

Sounds like a head gasket problem.

 

[eDiTicX]

Let's hope its just the cap ;D haha. But seriously, head gasket would suck. I actually have it warming up to temp now. There was no overheating associated with the overflow though? No milky oil. It does look as if there is some leakage from the exhaust manifold and when I ran sea foam through it, it showed me where the manifold was letting air out. But that's an entirely different thread.