A/C Blower motor relay

ANDY BOYER

MEMBER
2004 JEEP GRAND CHEROKEE
4.7L
V8
AWD
AUTOMATIC
118,000 MILES

Hi, my heat/air conditioner blower motor only works on high. I have replaced the blower motor relay. The problem was fixed temporarily (like one day), but now I have the same problem. I am not sure what my next step would be. Should I look at the blower motor itself? Sounds like I should also double check the new blower relay/resistor to make sure it is not defective? Thanks for your help.

Thursday, November 10th, 2016 AT 9:57 AM

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

We need to suspect the blower motor controller is the issue on this type of problem. However, it could be the HVAC controller not sending the signal for the other speeds.

I am attaching the wiring diagram and we need to test the supply voltage coming into the blower motor controller. It should increase as the speed is increased.

I am attaching the process on how to replace the controller which is the most likely cause but we need to do this testing and go from there.

https://www.2carpros.com/articles/low-or-no-air-flow-from-vents

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-wiring

Let us know what you find and what questions you have and we can go from there. Thanks

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