Chrysler Repair/cooling fan system circuit: '01 Sebring conv't
QUESTION: I have a 2001 Chrysler Sebring Convertible with a 2.7 V-6 Motor. I have tried to changing the fuses and Relays. I used other relays in the box. I tried to check the Fans. I ground out the pins 1 and 2. I used a third jumper and to activate the 3 and 4 pin with positive juice. I have high and low speed fans. How do I test the Relays to the controller?
ANSWER: Hi Edward,
My suspicion would be the coolant temp sensor is not reading the correct resistance for the temperature of the coolant. It should around 4,000 ohms when cold, then drop down proportionately to about 1,000 ohm or less when it gets into the range where the relays would be called into action. Remove the plug from the sensor and measure the resistance across its contacts as the engine warms up. The black/light blue wire on pin 2 goes to pin 43 at the pcm and is a common ground point for many sensors. The tan/black wire on pin 1 goes to pin 26 of the pcm and is the 'signal' wire.
The pcm activates the relays by grounding the outboard most pin of each relay socket when it observes the coolant temp sensor resistance to have dropped to a low enough resistance to ask for the low or high speed fan. So you could remove the relays and measure to verify whether the outboard pin of the low speed fan socket show 0 ohms to ground when the coolant reaches around 195F and for the high speed relay outboard most pin at around 210F.
Please 'rate/nominate my answer/me (see the PS below).
---------- FOLLOW-UP ----------
QUESTION: That could be. I recently changed the whole housing. I tried moving the relays inside the fuse block. I can not get the fan to come on with the a/c turned on.
Either the pcm is not grounding the relay activation coils or the 12v from fuse 23 on the other end of the relay coils is absent. The AC request should close the low speed relay immediately. So verify that you have 12v on the inboard pin socket of both relays when the key is in the run position, and then see if the outboard pin of the low speed relay is shorted to ground then you request AC. That relay should click when in the socket and you request AC if so.
Thanks for the rating/nomination. You can do both again if you would care too.