R & R of Blower Motor:
 
Application – 1989-90 full-size GM Blower Motor
 
Avanti Motor Corporation must have installed the engine and related systems BEFORE installing
 the inner fenders because there is no way to remove the blower motor.  Therefore rather than
 major disassembly, I opted to cut out a small circular section of the inner fender – just in
 front of the blower motor – to allow room for this replacement.  I utilized a pneumatic jig
 saw with short universal blade. 
 
Repair steps:
 
1.  Remove the front left wheel.
2.  Remove the inner fender liner
3.  Scribe the line you want to cut on the inner fender (from inside the wheel well).  
Carefully check to ensure adequate clearance, specifically any wires.
4.  Wearing protective equipment (eyes, ears, hands, clothes, etc.), cut the inner 
fiberglas fender as scribed.
5.  Unplug blower motor.
6.  Remove 4 or 5 screws attaching blower motor and remove motor.
7.  Install new motor – a new seal may need to be fabricated if original is damaged.
8.  Plug new motor into original wiring loom.  If connectors are different (as mine were),
 cut off all plug, crimp on new female prong to power lead (coming from the blower control
 module).  The ground wire simply needs to be connected to one of the screws holding the
 motor to the firewall.
9.  Replace wires to original location.
10. The section cut out of the inner fender may or may not be put back into place.  For 
the time being, I opted to leave it out to see if engine cooling might be better because
 of the opening.
11.  Reinstall the inner fender liner and wheel.

Blower Motor Relay:
 
I suspected the brushes on the blower motor were worn because the motor sometimes refused 
to come on and by tapping the motor I could get it to come on.  However, I recently 
experienced something different - I shut the car off, removed the key and was about to get
 out when I realized the blower was still blowing.  Strange - no power, no key, but the 
blower was still on.  Research revealed the Blower Control Module had malfunctioned.  This
 is a module that slips down into the blower housing.  It can be identified by the two 
plugs at the extreme corner of the engine bay, passenger side obviously towards the firewall.
  The module is removed by unscrewing two sheet metal screws that attach it.  Unplug the two
 plugs (one has two prongs but a single red wire, and the other has 4 blades but only 3 wires)
 - the two prong plug provides the incoming power.  In my case, the module had malfunctioned
 and continued to send power to the second plug which controls the blower motor.
 
The original module has the P/N DELCO 16061602 stamped on it.  This P/N was not valid in any
 database that was searched.  After calling GM and their CarTech Part Search (done by local 
Chevy dealer), the replacement P/N 12484912 was found.  Also listed as the AC-Delco 
P/N #15-72530.
 
This newer module mounts the same but the module and aluminum cooling fins
are different from the original.  However the existing plugs perfectly fit this new module
 and the system now works as it should.  One important thing to make note of is that for
 reasons that escape me, this particular module is not the one GM used in the blower housing 
Avanti uses BECAUSE you have to trim one corner of the module (snip off about one inch at a 
45 degree angle) in order for the module to drop down into the housing properly.  Avanti Motors
 used some liquid sealant which you may or may not have to renew when installing the new
 module.
 
Cost of the new module was $120 in January, 2005.  List is $169, so I don't know if I got a 
good deal or not - I didn't argue the cost - I was appreciative of all the time the Parts 
Counter guys took to find this new part number (I had been to 4 sources trying to get help!)
 
BTW, I'm told this module fits many GM applications from 1986 through 1991.

Good Luck - let us know how it turns out.
Rich

Richard Morris
Renton, WA