97 Deville Cadillac No Heat or A/C


Old 01-22-04, 11:05 AM
Visiting Guest
Posts: n/a
Question 97 Deville Cadillac No Heat or A/C

Suddenly I lost the blower and any heat or A/C. Fuses seem OK unless there is an inline one I can't find. In fact, I can't even find where the blower is. I want to check the voltage at the fan if I could only locate it. It's cold out there... any help greatly appreciated. I did pull the diagnostic codes off the dash.. not sure what they mean as it relates to this problem.

codes and my guess on what they represent (not sure is they are accurate)
MSM B0856 Dirty Battery
MSM B1983 Bat/source low voltage
MSM U1300 Class 2 shorted to ground
MSM U1136 Loss of serial communications for class 2 devices
PO 300 ???
PO603 ???

thank you
Sponsored Links
Old 01-22-04, 03:24 PM
Join Date: Apr 2002
Location: Pittsburgh,Pa
Posts: 2,417
The blower motor is under the hood on the firewall.If you have a class 2 short to ground my guess is the hvac is the location of the fault but it could be elsewhere.You may have a hard time with this one you will need at the minimum a entire wiring diagram for the car and a tech 2 would be a big bonus.But check for power and ground at the blower maybe you will be lucky and the class 2 fault will be a history code.Also check your battery connections and your grounds on the engine.A alternator output test wouldn't hurt.Keep us posted.
Old 01-23-04, 06:08 PM
msargent's Avatar
Join Date: Jan 2003
Location: Arkansas
Posts: 469
Many GM cars have done away with the old blower motor resister, and put a blower control module in it's place. These things will cause the symptoms you've talked about.. It's also located under the hood, up near the windshield...

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes