Chrysler Repair: 98 ATC blower runs on high only:Concorde, chrysler concorde lxi, 1998 chrysler concorde lxi


Question
1998 chrysler Concorde LXI has automatic controls turn the car on and blower motor runs on high only have to pull fuse on side of dash to stop motor. Have replaced the resistor and it worked for a day and started running on high again.

Answer
Hi Robert,
I assume that you have automatic temperature unit. The failure of the ATC power module is typically why the blower runs on high and without control to stop it. If indeed you replaced the power module then either it failed again or there is a problem with the communication from the ATC to the body control module which then controls the blower via the power module.
I don't know how to verify whether the power module failed again or not. You could check that the connection from pin 6 at the black plug of the bcm to pin 3 at the power module is patent (red/light green wire). Also check that the black wire on pin 2 of the power module is indeed grounded. If it is then you might want to see if you can get a free replacement from whoever sold you the power module. Otherwise the only other possibilities are that the bcm is faulty but that is expensive OR the blower motor is drawing too much current and needs replacement.
It would be good to try the self-diagnostic capability of the ATC control. Set the temp to 75, start the engine but don't drive it, then simultaneously press and hold the floor, mix, and defrost buttons. When the readout begins to blink release the buttons then wait to see if any two digit numbers come up. If so, let me know what it was. Then press the panel button to see if a second two-digit number appears, etc.
Please see the PS below.
Thanks,
Roland

Add on answer:
Roland did the diag test to get the codes for the ATC and it flashed 36 and 26. What are the repairs for this since that test I have replaced the ATC resistor and blower motor.

The 26 is 'ATC in-car temp sensor thermistor failure and the 36 ATC control communication failure. The former would result in a problem with the temp control being flaky, while the latter would be possibly cause the blower malfunctioning.
The possibility is that there is a wiring problem between the body control module plug 2 and the thermistor as well as the blower controller. That plug is black and the thermistor is on a wire at pin 22 to pin 7 at the ATC while the blower is on a wire at pin 6 to pin 3 at the blower motor power mudule, so check those connections. You also could check fuses 4,14, 16, 18, and 19 in the dash as those power the bcm itself.
Please consider rating/nominating me.
Thanks,
Roland.
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