Team Chevelle banner
  • Hey everyone! Enter your ride HERE to be a part May's Ride of the Month Challenge!

1 - 8 of 8 Posts

·
Gold Founding Member
Joined
·
63,816 Posts
Discussion Starter · #1 ·
I just put a new heater core in my granddaughter's 1990 Cadillac Sedan Deville (which is a piece of junk) but there is another problem now.
The blower motor will not come on.

I can make the motor run on high speed by running 12 volts directly to the motor.
I tried tracing the positive wire back but I loose it where it goes through the firewall behind a bunch of relays.

Anyway my question is, does anyone know where I can find a wiring diagram on what operates the blower motor?

I have tested every fuse and all the relays but there must be another relay somewhere.

Think I'm going to run out to U-Wrenchit in the morning and see if I can find a fan speed module.
I need to look for a 95 Caprice hood anyway and Joe said he saw one there.
 

·
Premium Member
Joined
·
2,223 Posts
Dean

As can be expected the Cadillac HVAC is a complex system. You can take a second mortgage and have your local Cadillac dealer fix it.

The Climate Control Panel (CCP) will display trouble codes. There are E codes that are problems detected by the Engine Control Module (ECM) and F codes that are problems detected by the Body Control Module (BCM). The E and F codes can be either intermittent or hard codes. There are also EE and FF codes that are only hard codes (currently in the abnormal condition). The codes are displayed for two seconds each starting with the E codes then the EE codes then F and last the FF.

To enter the self diagnosis mode, with the ignition on engine not running, press both the OFF and WARMER buttons at the same time and hold. The display will display 888, segment test, then the codes will be displayed. To exit the diag mode press the AUTO button. Press OFF and LO to clear BCM codes and OFF and HI to clear ECM codes.

The blower has a Climate Control Power Module on the right side of the firewall, just to the left of the blower motor. It has power in (red wire), ground (black wire), control signal in (ppl/wht wire) and power to blower (ppl wire). The control signal comes from the BCM not sure what signal this is but believe to be more than just power/no power, like a serial data or an analog signal. Sorry didn't take time to find the specifics.

Post any codes, there's to many to list. I'll get info on them.
 

·
Gold Founding Member
Joined
·
63,816 Posts
Discussion Starter · #3 ·
Thanks a bunch Elree !

I put a used "Climate Control Power Module" on it a while ago and the blower does work on all speeds now ....BUT
Once in a while with the key out, doors closed and everything off, the blower motor comes on for a few seconds then goes back off.
I might just add another N.O. - key operated relay to stop that.
Also there is a relay in the bank of relays up behind the glove compartment that keeps going clickedy click, clickedy click, clickedy click for a while after turning off the ignition.
I have no idea what any of those relays are for (except for the one that I know stops the blower motor when I remove it) so I'm thinking about leaving it out and see what does not work.

Now that I think about it, I remember when the car belonged to my X-son in-law and he would come over and park it I remember telling him the blower motor was running.
I guess the module has been replaced before because the old one had a $78.00 price tag sticker on it.

As soon as I get a chance I'll go back out and check for codes.
Charging the battery right now since I replaced the courtesy light fuse and left the dome light on all night.


By the way, the time delay start relay on my air compressor is still working great
Thanks again.
 

·
Premium Member
Joined
·
2,223 Posts
E 52 Indicates that the ECM memory has been reset or erased. Likely caused by disconnection the battery.

E 91 Indicates the park/neutral switch closed, 4th gear switch open and speed between 23 and 35 MPH for 10 seconds.

F 49 "High temp clutch disengage" Indicates engine coolant temp exceeded 259 F or high pressure refrigerant temp exceeds 200 F.

I would clear the codes, run the system and see if any new codes come in.
 

·
Gold Founding Member
Joined
·
63,816 Posts
Discussion Starter · #6 ·
Originally posted by Elree Colby:
E 52 Indicates that the ECM memory has been reset or erased. Likely caused by disconnection the battery.

yep, had the battery disconnected a couple of times

E 91 Indicates the park/neutral switch closed, 4th gear switch open and speed between 23 and 35 MPH for 10 seconds.


:confused:



F 49 "High temp clutch disengage" Indicates engine coolant temp exceeded 259 F or high pressure refrigerant temp exceeds 200 F.


That makes sense, the radiator leaks like seive
(No refrigerant in the system and the LP switch is unplugged.)



I would clear the codes, run the system and see if any new codes come in.
Tried holding the "OFF" & "LOW" and the "OFF" & "HI" buttons in but it still has the same codes.

This car really belongs in the junk yard itself but she ain't got no money for another car.

Radiator is shot, she has to carry antifreeze with her.
PS leaks so bad she has to drive it without PS fluid.
all down the right side was wrecked by her drunk father hitting a parked car.

Drips oil everywhere except the rear end but that's only because it's a front wheel drive.


Radio has been ripped out :(

AND it's a trash dumpster on wheels :(
 

·
Premium Member
Joined
·
13,924 Posts
Now I know why I don't work on Caddys. I think I might bite the bullet and find a better beater for her. JMHO.
 
1 - 8 of 8 Posts
Top