My heater works sometimes and dosnt other times.
I hear a clicking in the dash and took the glove box liner out and see 3 little relay looking things (black little box type things).
This is what clicks about 5-6 times before heater cuts out and stops working.What are these called so I know what to ask for at the parts store?

thanks if anyone can help.

PS, its not my heater control because ive already bought 2 good ones and the same thing.now i have 3 heater controls but i got them cheap so no worries.

 

By heater you mean fan right... Does it work on all fan speed settings?

 

After I hear the clicks in the dash, then the entire heater control goes out and does nothing.

its a digital control and the lights go out and it just dies.

and yes all settings work when it is lighted up on the digital display, when it dies it does nothing, heat-AC, all dead when the display stops showing anything...which is right after the click click click

 

Ok. I just took a quick scan of the TSBs for this system in your truck. Two TSBs stuck out.

One detailed as being erratic operation or flashing of the control head and stated that the terminals may be corroded on the back of the control head. It stated to clean/polish the terminals with a pencil eraser.

The other explained where there were two areas that the HVAC harness would chafe and possibly short out. One of those areas was where the six way I/P to HVAC connector terminals would short out against the ashtray. THe connector has slots to accommodate the terminal positive attachment locks that allow metal to metal contact between exposed terminasls and the ashtray. The other was the HVAC harness from the control head to the blower and mode door motors, running across the vehicle just under the dash panel. This harness may chafe against the cassette deck support bracket.