Fan will not stop

mcioffi · 01-29-2003, 09:54 PM

Anyone have any idea why the fan on my 99 Grand Cherokee woudl just keep running? It is 22 degrees, the engine is not over heating. It ran the battery and I'm having problems getting it started. Does anyone have any thoughts on this? I'm hoping it is not a major fix.

Thanks,
Matt.

automan25 · 01-30-2003, 03:12 PM

Does the fan remain on, even when the car is off? What about when the key is in the on position, but the engine isn't running?

I'm not an expert on this, but here is my theory:

The coolant temperture sensor is probably used to read the heat of the engine. Then the computer determines if the fan should turn on or not. If so then the computer triggers a relay to turn on the fan.

Since your vehicle still works, your computer isn't bad. Car computers are not like the Windows OS; car computers either work correctly, or they don't work at all. I would say that the relay that turns on the fan has gone bad. Relays tend to take a lot of abuse since they are constantly turning on and off. In your case it could very well just be stuck in the closed position, completing the circuit, and making the fan run. I would check that first. If that is the problem it would also be a cheap fix. You'll have to refer to your auto manual to find out where it's located.

mcioffi · 01-30-2003, 03:38 PM

I was thinking something like that, a clutch or a sensor or even a switch. To make matters the battery was drained and it is having major problems starting. I have been told that Chryslers have a problem after the battery has died, they need to be told how to start again.

To answer your other questions:
I connected the jumper cables and the fan turned on right away. I truned the key to the on position and the fan was still running. Basically the moment it got power the fan started running and would not stop. This morning it finally stopped running when the jumper cables where connected. But it had a hard time starting up. It did a few times but everytime it died if I did not keep my foot on the gas and it smelled like gas really bad.

It is at the shop right now, good guy, he is a family friend and will not fix things that are not broken.

Wish me luck,
Thanks again.
Matt.

automan25 · 01-30-2003, 05:25 PM

The last time I disconnected my battery my I had an interesting experience. In my case, all of the lights on the car began flashing when I hooked the battery back up. The car would also start, but only run for 5 seconds, and then die. Come to find out that this is actually a security feature...it's part of the alarm system. What I needed to do was to lock the car, and then unlock it from the drivers side door with my key. That reset everything. Perhaps this is happening on your Jeep as well?

Good luck with the fan problem, hopefully your mechanic will solve the problem.

01-30-2003, 03:12 PM	#2
automan25 Registered User Join Date: Dec 2002 Location: Kenmore, WA Posts: 292 Profile Gallery Classifieds My Jeeps	Does the fan remain on, even when the car is off? What about when the key is in the on position, but the engine isn't running? I'm not an expert on this, but here is my theory: The coolant temperture sensor is probably used to read the heat of the engine. Then the computer determines if the fan should turn on or not. If so then the computer triggers a relay to turn on the fan. Since your vehicle still works, your computer isn't bad. Car computers are not like the Windows OS; car computers either work correctly, or they don't work at all. I would say that the relay that turns on the fan has gone bad. Relays tend to take a lot of abuse since they are constantly turning on and off. In your case it could very well just be stuck in the closed position, completing the circuit, and making the fan run. I would check that first. If that is the problem it would also be a cheap fix. You'll have to refer to your auto manual to find out where it's located. __________________ 1993 ZJ Limited 5.2 - no mods - Red with Gold (what were they thinking) trim.

01-30-2003, 03:38 PM	#3
mcioffi Registered User Join Date: Dec 2002 Location: North of Boston Posts: 9 Profile Gallery Classifieds My Jeeps	Thanks for the reply I was thinking something like that, a clutch or a sensor or even a switch. To make matters the battery was drained and it is having major problems starting. I have been told that Chryslers have a problem after the battery has died, they need to be told how to start again. To answer your other questions: I connected the jumper cables and the fan turned on right away. I truned the key to the on position and the fan was still running. Basically the moment it got power the fan started running and would not stop. This morning it finally stopped running when the jumper cables where connected. But it had a hard time starting up. It did a few times but everytime it died if I did not keep my foot on the gas and it smelled like gas really bad. It is at the shop right now, good guy, he is a family friend and will not fix things that are not broken. Wish me luck, Thanks again. Matt.

01-30-2003, 05:25 PM	#4
automan25 Registered User Join Date: Dec 2002 Location: Kenmore, WA Posts: 292 Profile Gallery Classifieds My Jeeps	The last time I disconnected my battery my I had an interesting experience. In my case, all of the lights on the car began flashing when I hooked the battery back up. The car would also start, but only run for 5 seconds, and then die. Come to find out that this is actually a security feature...it's part of the alarm system. What I needed to do was to lock the car, and then unlock it from the drivers side door with my key. That reset everything. Perhaps this is happening on your Jeep as well? Good luck with the fan problem, hopefully your mechanic will solve the problem. __________________ 1993 ZJ Limited 5.2 - no mods - Red with Gold (what were they thinking) trim.