Overheating problem

[RetNav]

My wife's car is a 1997 Chrysler Concorde LXI with the 3.5L V6. It has 2 electric cooling fans and neither of them come on. The 40A fuse is good. Can't find a wiring diagram and was wondering if anyone on here was familiar with this setup that would be willing to share info?

 

[Paul Moir]

Re: Overheating problem

Mabey this from the 1st gen 'Trep forums might help?

 

[RetNav]

Re: Overheating problem

Thanks Paul, Maybe by checking all of the relays and fuses and then tracing wires I can get it fixed.

 

[Paul Moir]

Re: Overheating problem

The common ground on the fans would be the first thing I would go after. I take it the temp guage on the dash works. <br />Both relays are ultimatly under the control of the PCM; I can't see it being responsible unless it's getting bad information from the engine's thermometer, since they're independant of one another.

 

[Xcusme]

Re: Overheating problem

You may have 2 therm. sensors, one for the dash temp guage , the other for the PCM. I would think that you would have major driveability issues if the sensor to the PCM was reading low, no closed loop operation. My fans turn on at 214-220F. Most of the time, I can't hear them turn on at all, I just see the temp guage fall when they kick in. Is you motor overheating?? You could find the fan relay PCM control line and ground it. This will close the fan relay and the fan should spin. This would verify that the relay is good and the fan is OK.

 

[Paul Moir]

Re: Overheating problem

There is only one tempurature sensor on the 3.5, at least on 1st gen LHSes, and it runs the PCM and the dash indicator. The two fans are controlled independantly, so one or two turn on as the temp picks up. One or the other also come on depending on the A/C pressure. So there are two relays, two fans, etc. I think it's more likely there's a single point failure. But it could be two (staged) failures, since if one fan died, you might not notice the tempurature bump.

 

[RetNav]

Re: Overheating problem

Thanks,<br /> The motor is definitely overheating and the gauge shows on the dash. <br /><br /> After talking with Paul yesterday, I pulled both fan relays, swapped them and fired up the car with the AC on. Both fans came on within 60 seconds. Checked it three times with same results. I am going to drive it again this AM to give it a good check. It acted as if the relays were not making good contact and swapping made them work. Who Knows.