QuestionQUESTION: Engine cooling fans run at high speed anytime car is running. Does not come on with key only, just when engine is running. Replaced relays with no change in condition. Have also found that A/C clutch will not engage. Changed relay there as well with no results. Am able to jump across relay to engage clutch. Cold air when engaged. Light in switch works and there is power coming from switch. There is freon in the system. Pressures look good. Since cooling fans normally come on when A/C is in use, I assume that the two issues are related. Any suggestions? Thanks!
ANSWER: You didn't say the year/make/model/engine so I can't be too helpful except wonder if the engine temp sensor is faulty or perhaps a short to ground in the wire which activates the high speed fan relay. Seeking a diagnostic fault code would be a second approach which may point specifically to what the engine controller has noticed to be wrong. So fill me in on the specifics of the vehicle, please.
Roland
PS Sorry for the delay but I just found your question in the 'pool' to which it had been referred by Kevin, the other Chrysler expert.
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QUESTION: Sorry Roland. It's a 1997 Chrysler Sebring JX convertible with a 2.5 V6. I thought of the temp sensor also but dismissed it because the temp gauge still works fine. Is there more than one temperature sending unit? There are no codes in the system.
AnswerHi Dan.
The temp gauge and the engine temp sensor is one and the same. I have a couple of possibilities:
There is also a trans fluid temp sensor inside the trans which could be faulty or have a circuit issue which would turn on the fan falsely. Read the resistance betweens pin 54 and 13 of the TCM to see what the reading is cold and and when the engine/trans have been driven to operating temperature. I an not certain of the spec but if it is like the ect sensor it should be several k ohm when cold and drop to near 1k when hot. Then pull the plug on the pcm that has pin 69 and see whether the dark blue/pink wire on that pin might be shorted to ground between it and the high speed relay socket (remove the relay to isolate the wire entirely).
On the AC not coming on, that might be too high a charge of refrigerant in the system, or a false temp reading in the HVAC box for the fin sensor. See what the voltage reading is between the A and C pins of the pressure transducer which I believe if above 4.51v is too high. Read the resistance across the evap temp sensor where there is a 2-wire disconnect on the right side of the HVAC housing adjacent to the blower motor housing. The wires are light green/black and gray.
Roland
PS Please rate my answer and consider a 'nomination'. Thanks
