2007 Dodge Ram 1500 w/ 5.7 Hemi

The condenser fan is not turning on. The AC compressor was short cycling causing the motor to almost stall at idle.


I replaced the condenser fan and no change. Changed the AC pressure switch then evacuated and recharged the AC system with recommended amount of 134a. The compressor has stopped short cycling but the condenser fan still wont come on.

There is power to the condenser fan connector, also the fan will run when hooked directly to the battery.

My model Ram doesn't have any relays

What am I missing?

 

What year and model is your truck?

 

2007 1500 with 5.7 Hemi

 

Are you sure your truck doesn't have ANY relays in the fuse box that can be checked? Does tapping the fan with a screwdriver/hammer make it kick on at all? I would also check the condition of the wires that connect to the computer(s) on the truck.

 

I am pretty sure there are no relays. I believe the relays are built into the fuse box. Tapping the fan does nothing. Its a brand new fan. The fan runs when hot wired to the battery. Wires all look ok from what I can see?

 

A wiring schematic would be very helpful. Just throwing this out there. Is it possible you have a bad dash selector switch?
Are there any other modules for this system ?
Being an old guy I'm way out of date with constantly evolving wiring systems...but I try. I recently got involved with a inoperable passenger seat heating on a 07. This computer board switch controlled high and low heat to both front seats and 4 way flashers and only had a 3 wire connector! How do 3 wires control all these functions!!??? Amazing. There was a separate module for the heated seats....and a replacement switch fixed my issue.
Anyways. You have 12v at the fan connector so it seems your missing the required ground signal to complete the circuit at appropriate times. The A/C runs in A/C mode and defrost mode. Does the dash switch control the ground signal via the PCM or another module ? Just an idea. Let us know how you make out

 

Thats a good thought. The switch appears to function properly between selections and speeds but I am not sure how that impacts the condenser fan. I will check into it.

 

Did you see the thread started May 7 titled dual zone climate control. Might find it interesting

 

yes, after you mentioned it I went and read through the thread. Thanks for bringing it to my attention. Anyone else have any ideas? Only things left are the TIPM and wiring. Did a visual inspection of both and they appeared to be ok.

 

I found a YouTube for fan relays from 01 to 08. Carpros . sorry can't link it for some reason . Not sure if yours is the same.

https://youtu.be/_wyb8rr6EWI