slushman

F150 1998 V6 extended cab

I replaced the factory cassette deck with a CD and had to take the heater control out. Simply unplugged it and plugged it back.

Now after every thing put back in the system is stuck at defogger. The air output does not switch to floor or pannel when doing so by the control ****.

I have been having issues in past where my A/C will kick in even when I am on Flooor/Pannel setting.

What should I start looking at ? Did my unplug and plugging harness did something and now I need to do some sort of reset ?

Any help is appreciated.
Thanks

brad22482

I had a very similar issue when my a/c would only run on defogger. I read it was possibly due to a loss in suction. Sure enough one of my air hoses (one that was hooked up to the egr valve) was rotted through. Check all of you air hoses for leaks

TRD-Toy

The a/c coming in with floor/vent is normal all depends where the temperature is set at. F150 and my F350 do the same thing. I would check that you vacuum to the contol head should be the black vacuum hose to the control head. If you do have vacuum most likely the control head is bad or unplugged yet. If you don't have vacuum at the head check the connection by the blower motor. Defrost is the default mode if you lose vacuum. Under the hood behind the battery is also a good place to look for cracked broken vacuum lines. There will be a vacuum one-way check valve by the battery, will be the vacuum line that feeds the control head. The is no reset for the system. Check your vacuum at the control head, pinched off/broken hose is my guess.

4by4ford

The o rings in the control head will go bad also, I had this problem in a 03 crown vic, took apart the control head and replaced the o rings and it worked fine again. The radio work might be a coincidence.

greenheadkiller98

I had the same problem with my truck. My fix was there was a vaccum hose that came out the grommit in the firewall. All i did was stick the hose back in. Problem solved, although something else mite be causing yours. If i remember correctly, the hose is on the passenger side and i was a common problem because passengers feet would sometimes pull the hose out.

slushman

Thanks for all your responses. This is awesome forum !!

For some odd reason I started the truck next morning and all seems to work just fine. Might be the vacuume system reset after some time

I still went ahead and inspected all my hoses and make sure all is connected well. To my surprise all in a good shape for a 1998 truck.

Now on to find front right speaker