Chrysler Repair: 1996 Intrepid cooling fan operation, fan steps, fan operation

Question
Hi Roland:



Hope all is well with you. I am again working on my wife's 96 Intrepid. The cooling fans decided to stop working yesterday. No codes were set.



I began by checking all fuses, hi & lo relays and connection to temp sensor today, and through sheer luck (probably a dirty connection somewhere# some fan operation has been restored. I say some because I know things are not operating correctly yet, thus my questions to you.

What I found is this; when engine temp reaches approximately 213 degrees #according to the data feed on my scan tool# the right #passenger side# fan starts. If the temperature goes above 225 degrees, the fan steps up to high speed. The left fan #driver side) does not operate under any condition that I have observed. I tried running the engine up to temperature and blocking the radiator temporarily to raise temps up to observe fan operation. I had A/C on, off and set the controls in all positions. no matter what I did, the left fan did not operate. I have not yet accessed it to test it directly, but had taken a break and thought I would see if you could advise how the fans SHOULD work? I assume that I can jump 12V directly to the fan to see if it will run, and also could check continuity. It is not physically stuck and will turn freely. It just won't run.

Appreciate any guidance you could offer.

Thanks & take care,

John

Answer
Hi John,
Unfortunately I don't have the '96 manual but I suspect the '98 manual is applicable. More unfortunately is that neither manual really describes how the fans are supposed to operate although after looking at the '04 manual I believe that the two fans are identical and whenever fans are called for both fans should run simultaneously. The '04 manual finally spells out that when the temp first calls for fans that both fans come on at low speed because they are wired in that mode to run in series. When the temperature rises futher, then the the relays change the wiring so that the fans run in parallel and thus 'see' the full 12V rather than each seeing 6V. The wiring diagrams are not all that clear in any case but I would believe that your best starting point would be to jump 12v to the left fan to see if it will run at all. If it does then the there is an issue with one of the relays or the wiring of it, if it doesn't then the motor needs to be replaced. The wires to the fan motors are different between the '94 and the '98 manual so if you would be so kind as to tell me the wires that go directly to the left and to the right motor in your '96 that would be very helpful to me.
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Thanks,
Roland