87 5ktq Climate control issues....

[Michael Murphy]

"Beatty, Robert" wrote:
> 
> Hey gang,
> 
> Posted on this before and havent really been able to nail it down.  Problem
> is this....
> 
> Start car up in the morning.  Defroster works great on low and high.  Go
> home from work 9 hours later, still working just fine.  Park the car at home
> for an hour,  still working great when we go to the store.  30 minutes
> later, leaving the store, no fan at all.  Has happend in the past and im
> buying a blower motor to rebuild and install.  My question is this... Is it
> more likely to be the CC control unit? or worn brushes in the motor?  No
> matter what ill have a rebuilt blower to install once i do the work, so if
> its the control unit i can replace that too.
> 
> Thanks in advance
> 
> Rob

WAG says it's the blower motor but, is there any possibility you can
check the power at the blower connection when the problem occurs?  Would
mean you have to drive around with the phlenum cover off and a
multimeter in the car.  

When the fan doesn't run, pull the power connector off the blower motor
and check the voltage/lack thereof.  If it reads +6VDC on low fan and
+12VDC on hi setting, then likely it's the blower itself.  If you have
no/out of range readings, then the problem lies downstream in the
controller, wiring or the CC head.
hth,
Mike Murphy