1st gen 3.5 LHS (1996) cooling

So what you're seeing seems fishy.

The engine cooling fans for the 2nd gen do in fact act in tandem, i.e., they both are at the same speed (both off, both lo sped, both hi speed) at any given moment. I'm not sure if the 1st gen does the same thing, but I wondered about that too. You'd have to look at the schematics for the first gen.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

I have some manual information in '94 LH cars that says "On models with dual electric fans, fans operate through a common relay and are activated at same time." I don't know where I got this document that I have - it does not appear to be direct from Chrysler, and I tend to distrust aftermarket service information. But it sounds like it is a safe bet that the fans should be working together like Joe said.

Could be a relay, fan motor, or wiring problem. It would be best if you had the schematics.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

"Could be a relay, fan motor, or wiring problem. It would be best if you had the schematics."

yeah that was another reason i wanted to change the temp sensor aside from the fact the resistance seemed off. i wanted to make sure i was getting a good signal to everything. so i need to find what schematics i do have and go from there.

You're not mistaken. You have a bad fan motor on the passenger's side. Just finished fixing a similar problem on my wife's '93. The right-side motor is a screwball thing with two sets of winding. On low speed, one of its windings is powered from the car, the other acts as a generator and drives the left-side fan. This causes both fans spin slowly on low speed. On high speed, power is applied to the left fan directly and also to the set of windings that was acting as a generator on the right fan, so both fans get power directly from the car and spin fast. I think that later in the first-generation LH car run, they changed it up so that its one fan on low, BOTH fans on high. But either way, its never "one fan on low, the other fan on high."

really. ok that might seem possible since we use AC so much in Florida, the fan is running a lot. i didn't notice the passenger side fan seems to have a large motor housing. noticed the right one comes on even when its not hot, as long as the A/C is on.

when i hadn't quite gotten all the air out the first time Saturday, the gauge went to the half waypoint, right side fan came on, gauge moved a little bit more towards hot, then both came on at once and sped up some. so the extreme high seems to work, but i'll look into the right side fan anyway. Also wondering if A/C pressures are effecting it.

fan relays seem to work, but all the info i have is a diagram showing the color of one wire sending power to it and the pin number on the power connector that sends power to it. no info on which blade does what and what you should measure etc. anyway with low side relay out of the car the left fan kicks in and takes over. otherwise right side seems to do the work. so the 2 sets of wiring info you gave seems about right.

Wow. That is screwball. You sure about that? I'd love to see the schematics for that. Anyway you could email that to me?

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

ditto

found this today....

DESCRIPTION All models use electric motor driven fans. The fan modules include a motor support and shroud. The module is fastened to the radiator by screws with U-nuts and retaining clips.

OPERATION The dual fan module is a combination of 2 fans mounted in a one piece shroud which operate at two speeds and are simultaneously activated. The dual fan system improves engine cooling and air conditioning performance in hot weather and severe driving conditions, while reducing fan noise and power consumption.

CAUTION: Attempts to reduce high temperature gauge reading by increasing engine speed, at the same vehicle speed, can increase high temperature.

CIRCUIT OPERATION The radiator fan system uses two relays located in the Power Distribution Center (PDC) . One relay is used for LOW speed fan operation and the other is for HIGH speed operation. The Powertrain Control Module (PCM) controls the operation of the relays depending on engine coolant temperature and/or A/C operation.

Power for the coil side of both relays is provided on circuit F18. This circuit is protected by a 10 amp fuse located in cavity 20 of the junction block. Power for the contact side of the relays is provided on circuit A16. This circuit is protected by a 40 amp fuse located in cavity D of the PDC.

When LOW speed fan operation is required, the PCM grounds circuit C24. This causes the contacts in the relay to CLOSE connecting circuits A16 and C23. Circuit C23 connects from the relay, and is spliced to the low speed fan motor and the Radio Frequency Interference (RFI) suppression module. Ground for the motor is provided on circuit Z1, which terminates at the left front frame rail.

When HIGH speed fan operation is required the PCM grounds circuit C27. This causes the contacts in the relay to CLOSE connecting circuits A16 and C25. Circuit C25 connects from the relay, and is spliced to the high speed fan motor and the RFI suppression module. Ground for the motor is provided on circuit Z1, which terminates at the left front frame rail.

Copyright © 2008 ALLDATA LLC

Did that come from an Alldata account? If so, it should also give you access to the schematic right out of the FSM.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

rob wrote:

update. new fans working much better. new ones from local dealer were

700.00 bucks! i went parts jobber and got them for 254. now the only issue is a short in the high side. jumping it only turns on the low side fan so i'll need to do some wire searching tomorrow night.

yeah there's an updated TSB on the wiring diagram NUMBER: 26-10-95A

i can email it to you if you want.....

also found Cooling Fan - Noise/Poor Idle Quality NO: 18-20-96

I don't think its actually detailed in the FSM (Rob posted a very good verbal description from alldata in a subsequent post). I figured out what was going on with a DVM and some experimentation when my wife's car suffered its first fan motor casualty a few years back.

Bill Putney wrote:

Well, now I don't feel so bad about paying $280 (tax and shipping included) for my new module. It does still cheese me off that I can't still get a replacement passenger-side motor like I did the first time I had problems years ago. Everywhere I went they had plenty of DRIVER side motors- but in my experience they never fail. The original one on wife's

93 was still working fine.

254.00 for mine at CARQUEST. everyone else i called could get them in 3 days, but that does help me get back and forth to work.

WARNING! they and a lot of other parts dealers carry DORMAN? fans now and i was told this is a new product for them. i got my new one and it worked for about a day and half. the connections to the high side fan (drivers side) was loose all the time and the passenger side fan was doing all the work, but then it got to the point it got hot and stopped working. the parts guy that originally sold it to me said they have an issue with their quality from time to time (duhhhh) but its lifetime warranted. so out it came and back for another. works fine now.

also the parts guy at my local Chrysler told me he could maybe get me a right side motor if i needed one but there was only 7 or 8 left, and they would be about a week or 2 coming, and no guarantees on that. also he said they superseded it with the full unit (both fans and shroud) since they were only selling about 5 right side motors a year and that was nationwide!