1G 1g engine fan not working

[naw9119]

Hey guys Ive got some funny stuff going on with my engine fan. I was driving to work one night (mostly freeway at high speed) whe I get off the freeway my engine temp shoots up almost to over heating. I was right there at work so I just shot in the lot and cut it off. Opened the hood and the engine fan wasn't working. Made it home fine after work no temp problems. Checked the fuses, good.checked the relay good. Jumped the relay and both fans came on. Checked the temp sensor at the bottom of the radiator, no continuity cold haven't checked it hot yet. Jumped the sensor connector at the bottom of the radiator and the a/c fan came on. I know my next step is to check the sensor hot. But I'm a little confused. I thought jumping the radiator fan relay would turn on just the radiator fan not both. And I thought jumping the temp switch would turn on the radiator fan not the a/c fan. Any help with this would be greatly appreciated.

 

[1990AWD]

Try the a/c fan relay by the brake booster. I know it sounds weird but I once had the same issue and I swapped that and it worked.

 

[BLAKSUNSHINE]

Any luck in resolving the problem?A update would be appreciated!

 

[naw9119]

Nope everything is still te same. I won't have time to look at it in depth till this weekend. I just wanted to get some ideals of what it could be before hand.

 

[undefined0000]

Might be the sensor. You could always drive with the A/C button on. That turns on the fans. There is also a mod to power the fans with ignition found HERE did the mod at a gas station on my way home from Ohio on a 7 hour drive. Took like 10 mins and got me home.

 

[naw9119]

Sorry it took so long I had a oil leak I had to deal with. So I replaced the radiator fan switch. I took it for a drive and the pass side fan came on but it was still overheating so I turned the a/c on. The driver side fan never came on and when I turned the a/c off the pass side shut off. I turned the car off and jumped the rad fan relay and both fans came on. The only way to get the driverside fan on is to supply it with direct power or jump the rad fan relay?
Another thing, it doesn't over heat all the time. But when it does the gauge just shoots almost to overheating then drops just as quick. Could something be wrong with my gauge? Is there a way to test it? My coolant is always boiling when I get out of the car even if the guage says the temp is ok! Im lost

 

[iaintmaci]

I would double check your thermostat and radiator cap on the "boiling." The thermostat could be sticking shut, not allowing the coolant to flow properly, or the cap could be letting pressure escape causing the "Boiling" sound. Also, what type of coolant mixture are you running? I know I can run with my a/c fan on by itself and the car does not get hot at all. Sounds to me like something in the coolant system.

 

[naw9119]

I'm running a 50/50 mix should I change?

 

[iaintmaci]

That should be fine. If you have a completely sealed system, it raises the boiling point of the water or coolant in your engine. If you have a leak somewhere in that system, it will not allow the coolant to properly do its job. Like I said above, if the cap is going bad, it will sound like the coolant is boiling. I have actually sat and watched my radiator and overflow vibrating from the force of it on my Dakota. I thought it was a bad head gasket. I was randomly overheating, had the boiling effect, and losing coolant out of the overflow like mad. It turns out that my radiator cap went bad and was letting all of the pressure escape. In doing so, it was not allowing the thermostat work properly either. For the price of a new T-stat and rad cap, its worth a shot.

 

[naw9119]

I'll try that any thoughts on th fan issue?

 

[undefined0000]

I'm suspecting a bad relay. Take the relay for the A/C fan from the A/C box and put it in the spot for the radiator fan.

 

[iaintmaci]

If its not running at all, it may be a bad relay, fuse, wire, maybe sensor. I would check the sensor out. If it is showing up good, then I woul take a volt meter and start tracing wires and checking relays. The wiring on my car is all screwed up, so at the moment I have mine running off of the A/C button in the car. I am going to do a rewire and run it off of a toggle switch with keyed power. I could rewire it to the sensor, but I want to be able to have a little more control over it.