98 Caravan 3.3 Heater problem

[bwanamike57]

It all started when a cup of coffee was spilled on the temp control. Within minutes the heat began to decrease slowly until there was only cool air coming out of the vents. I have replaced the thermostat. Had the system flushed by the garage. I took apart the temp control and cleaned it. i replaced the heater core. I have run the engine with radiator cap off for 1 hour replacing fluid at the radiator to get air pockets out. After all this there is still no heat.

Have any suggestions? :help:

[McClane]

Hmmm, you have done everything I would have started to investigate as to why there would be no heat. Could it be the coffee spilt on the controls shorted a fuse ?

[bwanamike57]

Thanks for the reply, The temp gage reads correctly. In our previous Caravan '90 the thermostat would get stuck open and the temp gage showed that by registering very cool. In our '98 the temp gage reads normal and in fact i can feel heat at the heater core even through the plastic cover. This leads me to think something is not opening correctly in the blower.

As to the fuse idea i have not checked. All other buttons on the control operate correctly. but i will check for fuses. :)

[gas28man]

See my earlier thread about that control panel on your dash. It is electronically controlled, and spilling stuff on it apparently causes failure.

Rick

[bwanamike57]

Rick,

thanks for your Dr. Pepper comment. I confirmed that it was the control that is bad by doing a calibration check. with the engine running and fan on high and vent on face and temp control on cold - pushing the (rear)wiper and washer buttons simultaneously until all the LEDs light puts the controller into calibration. It then cycles through the different heating modes and sure enough real heat comes out through the vent for about 10 seconds until it moves to the next cycle. However in normal mode adjusting the heat control does not bring heat into the compartment.

I guess my next step is to find a salvage yard that has this exact controller. the parts dept at the dealer will charge over $300.

Thanks again.

[gas28man]

Hey, thanks for your reply. I didn't know that the calibration check also checked the heat. I thought it just checked A/C. Good to know.

Rick