Rad Fan Will Not Stop

[Rhunadan]

Hi folks,
When I shut the car off, the lower rad fan keeps running until it drains the battery. I think it might be a stuck relay, but I'd like to hear any other suggestions before I start swapping parts.

Thanks.

[transamtom1]

Re: Rad Fan Will Not Stop

Hi folks,
When I shut the car off, the lower rad fan keeps running until it drains the battery. I think it might be a stuck relay, but I'd like to hear any other suggestions before I start swapping parts.

Thanks.

That would be my guess, the relay.

[ssms5411]

Re: Rad Fan Will Not Stop

I would think its the relay also.

[thebeewantsboost]

Re: Rad Fan Will Not Stop

but its so easy to just switch relays. lol

[Rhunadan]

Re: Rad Fan Will Not Stop

Well, I replaced all the relays and that didn't solve the problem. Is there a sensor that triggers the ecu to trip the relays?

[transamtom1]

Re: Rad Fan Will Not Stop

The coolant temp sensor.

On the 3.8L. one sensor does both the gauge and PCM.

[2.8 Bird]

Re: Rad Fan Will Not Stop

I haven't really done any work on this but a cooling fan circuit has: cooling fan fuse, relay, coolant temperature sensor and the computer.

Perhaps the Coolant sensor is tripping the computer to keep it on. I would check on that.

[Rhunadan]

Re: Rad Fan Will Not Stop

Thanks gentlemen, I'll check it when I get home tonight.

[Rhunadan]

Re: Rad Fan Will Not Stop

I just came back from my local Car-quest on my lunch hour. When I asked for a coolant temp sensor, he asked if I wanted the gauge sensor or the ECU sensor. I didn't know there were two sensors. Since my gauge works fine, I bought the other. I'll see what happens when I install it tonight.

[Rhunadan]

Re: Rad Fan Will Not Stop

Well, I replaced the temp switch, and that didn't fix it. I replaced the one below the throttle body.If that's the wrong one, where is the one I'm looking for locawted?

[Rhunadan]

Re: Rad Fan Will Not Stop

Well, I replaced the temp switch, and that didn't fix it. I replaced the one below the throttle body.If that's the wrong one, where is the one I'm looking for located?

[transamtom1]

Re: Rad Fan Will Not Stop

I just came back from my local Car-quest on my lunch hour. When I asked for a coolant temp sensor, he asked if I wanted the gauge sensor or the ECU sensor. I didn't know there were two sensors. Since my gauge works fine, I bought the other. I'll see what happens when I install it tonight.

The 3.8L uses one sensor for both functions,the one below the throttle body is the one and only sensor.

Electrical problems can be a nightmare.

But I think you narrowed it down to a bad ground,look for all the black wires screwed to the chassis in the engine bay,also any braided metal straps.

Take the screws out use some sandpaper to clean the chassis and the ground ring and put them back.

You can touch them up with tremclad after you test your fans.

Goodluck.

[Rhunadan]

Re: Rad Fan Will Not Stop

Well, I thought I had the problem licked, but they still will not turn off. I'm starting to think its a computer issue, so I bought one fron a 97 5speed to try and see if that would fix it. The 97 should plug and play in my 96, right?

[techsan23]

Re: Rad Fan Will Not Stop

Well, I thought I had the problem licked, but they still will not turn off. I'm starting to think its a computer issue, so I bought one fron a 97 5speed to try and see if that would fix it. The 97 should plug and play in my 96, right?

Yup, as long as it matches the trans you have (manual or auto). If not you can have another vin flashed into it. With the 97' pcm you'll be able to tune it with hptuners, and set the fan on/off temps.

[ssms5411]

Re: Rad Fan Will Not Stop

I would check your relays.