L300 HVAC panel problems

I replaced the HVAC panel about 18 months ago because the blower switch had
failed. Was a bummer that just the switch alone was not available and only
came as part of the HVAC panel at about $170.

Yesterday, I had the blower on high and had the AC on. A little while later,
tried to turn off the AC and put the blower on low. The blower switch was
jammed in high and took a bit of wrestling to get it to a lower setting.

Noticed after this that the AC would not turn off. The AC button yellow led
turns on/off when the button is pressed but the compressor stays engaged and
the engine idle is always at 650-700 RPM (typical of when the AC is on).
This means that the BCM is getting an AC Request signal. The mode selector
switch is working normally but the recirculate button has no effect. Seems
to be stuck on outside air.

Until I trace out what happened, just pulled the 10A AC fuse from the UHFB
to disable the compressor. Still get the high idle. Didn't want to chance
damage to the compressor until I verify that the refrigerant pressure sensor
is working and find what happened in the control panel. Best guess is that
the fan speed switch failed again.

Oppie

** Posted from http://www.teranews.com **

 

I still had the original panel. Cleaned up the contacts on the fan switch as
they were a bit fried (and the reason I replaced the panel). Seems to work
properly now. When I get a chance, will tear down the old panel and see what
fried. Appears to be on the circuit board since got all the correct voltages
on the fan switch.

I also looked at the blower motor since the problem happened when the blower
was on high. The shaft did not turn as easily as expected and there appeared
to be some radial runout in the bearings. Not sure if the 'runout' was due
to rubber motor mounts. Would have to open it all up to see better.

** Posted from http://www.teranews.com **