This 1992 Cadillac Deville came in with no blower operation. I checked at the blower motor which is on the right side of the picture behind the bar that goes between the two front strut towers. No power was present with the key on and blower set to high. The blower power module is behind and underneath the under hood fuse box located at the firewall. The next step was to remove the cover. Two twist tabs .
One nut on the passenger side. Should have been a wing nut but this one had a hex nut.
There are two 10 mm nuts that have to be removed from the fuse box mount. This one is easy.
This one can be a pain. Not so hard to get out but difficult to get it back into place. I generally use some adhesive to hold the nut in my socket when installing.
With both nuts removed the fuse box can be moved away from the firewall. Did I mention you should unhook the battery?
With the fuse box far enough out of the way the next problem is plastic fuel lines that are in the way. I use a large screwdriver and pry the mounting clip off of the stud, along with my other hand in a rocking motion. This can be very difficult at times and care has to be taken to ensure the fuel lines do not get damaged.
For testing purposes I pulled the connectors up. First I had to remove retaining clips with a pair of needle nose pliers, then released the locking tabs and pulled the harnesses up. There is a better picture of the retaining clips later but at this point it was too dirty to make any thing out in a picture. There was 12 volts continuous power on the red wire, ground on the black wire, and a variable voltage on the small purple and white wire that changed with commands from the a/c control head with the ignition on of course. The large purple wire is the power supply wire to the blower motor. All signals were okay so I jumped power from the red wire to the large purple wire to see if the blower motor was okay. It was. Maximum current draw was 25 amps. I prefer lower but that was okay. Continuous current draw at high blower was 18 amps.
Luckily the inside of the a/c box was cleaner that the outside. I always look in to make sure the air flow is clear.
I installed the new power module.
Plugged in the harness connectors and installed the positive assurance clips. I tested the system and installed the fuse box and cover.
