warrenoliver

I have a 2007 F150 XLT that I just changed out the factory radio for an aftermarket one. ONce I put everything together, the heater fan no longer comes on. I just get a little warm air through the ducts when driving. I have continuity in the fan switch and I also jumpered the resistor plug and still get no fan. I reinstalled the factory radio and that did not change anything. Seems like the whole heat/AC module is dead. I don't hear the door open when I move the temperature switch and the AC does not come on when I push the button. Recirculation button also does not seem to work.
Seems like a fuse but the fuse tests good, I swapped with another and that didn't help. The relay I also swapped with a known good one and still nothing.

Going deer hunting tomorrow and will need heat!
Ideas?

Thanks.

Warren

vintageman

Do you have power at the actual plug to the fan, I know you said you checked the fuse and relay but it seems pretty strange that you had it before and now you don't. If you have power at the fuse but none at the plug at the fan, you gotta chase the wire and look for breaks.

warrenoliver

I do not have power to the fan plug unless I tested it incorrectly. The frustrating part of this is that I really didn't do anything with the heater controls. We popped the trim off the radio and only disconnected the air bag light at the top of the trim. All heater and blower controls were left alone.

It acts like a fuse is out but the only fuse I can see from the owners manual that controls the blower -#116 and the relay R06 both are good. I switched both of them with other known good ones and they are good. Is there by any chance another fuse that controls these controls? I did notice that tonight when the lights are on, the dash lights do light up for the fan control, temperature control and vent/AC selector. I still do not get any lights when I push the button for AC or recirculation.

I did change the resister with a new one on the outside chance that it was the problem but no luck.

Mod (Ret.)

My guess is that one of the plugs on the back of the radio/heater/A/C bezel that you left dangling while swapping the radio came loose. Pop off the bezel, and one at a time, remove, check, and re-install the fan control plug (this one has a sliding "lever" to allow it to unplug), and the center plug (it's several colored vacuum lines in the plug). One of these is not making a good connection, or one of the vacuum lines perhaps got pinched.

warrenoliver

Bucko,

Thanks for the suggestion. I removed the plug and the center plug. I wasn't sure how the individual wires come out of the center plug and I didn't want to force them and possibly break one off. I did make sure they were all seated correctly and they seemed good. I checked for power to these wires and there is power to some of them when unplugged so I am thinking the power is good up to that point. Of course the module that it plugs into is sealed so I can't really break that open I don't think. It just doesn't seem to be talking to the fan switch. I could not find any vacuum lines on this connector so I don't think a loose line is the issue - at least not at the radio trim plate.

Any other ideas? I am heading out for deer hunting with a 2 hour drive with no heat. I won't be able to work on it again until Monday.

Warren

warrenoliver

Anyone with any suggestions? Still no blower so very little heat reaches the cab. The blend door must be open to the heater instead of the outside air vent so that is good since the temperature is in the teens and 20's.

Is there any way to test the blower control module that has the blower switch, mode switch and temperature dial? I am wondering if that unit is bad.

techrep

iTrader: (1)

run 12VDC straight to the blower motor and see if it kicks on...

warrenoliver

OK, thanks. Just to make sure I don't blow fuses, of the two wires going to the motor, which is the hot one?

When I do this, I will have the blower set to high and the selector switch to direct air to vents and floor. Is that correct or should I set the switch on the #1 setting? I have changed out the resistor already so that part should be good.

Thanks

techrep

iTrader: (1)

what color are the 2 wires ?? and you should not need the switch at all...your running power straight to the motor to verify the motor works. or if your handy with a multimeter you can read power at the motor with the fan switch on...see what you get.

warrenoliver

Techrep,

Sorry about the delay. I have been grinding venison hamburger for the last day or so. I just jumpered the wires to the fan and it does turn on with 12 volt power when connected. It seemed to run on high speed which makes sense since it is not using the resistor. So it looks like the fan itself is good. Seems like something is not telling it to turn on.