'97 truck replacing HVAC fan tips ?

[schiker]

Ok I am pretty sure my HVAC fan is bad. I can jumper 12 to purple wire terminal on motor and it does not blow. Will double check ground but I did read continuity to frame so I am thinking ground is ok good.

So what are the tips and tricks to replacing the blower motor. Looks like its going to be a PITA.

 

[schiker]

Have ~ 1 ohm from black wire to jumper wire to battery Negative. Had about 7 ohms to the metal frame under the dash.

Just in case it has continuity but marginal current carring capacity....

I hooked 2 wires directly to motor: 1 to battery positive to purple wire terminal and 2nd wire from battery negative post to black wire terminal. Still no fan blowing so the motor is kaput I would say and needs to replaced or taken apart and checked brushes.

Those that have replaced the fan motor what all did you take out also? Did you take out the PCM? Did you take off the dash. I don't have an air bag to worry about so that makes it a little easier.

Any good Tips would be appreciated.

 

[ak diesel driver]

just the glove box , but it is tight

 

[great white]

remove glove box.

I used 1/4 drive sockets and a 1/4 drive t handle.

Mine had a rubber cover over it. I had to remove the PCM holder bracket to get it off without ripping it all to heck. I also just unplugged the PCM and pulled it out to help with access (I wouldn't both if you rmotor doesn't have this insulated cover).

The little blower motor cooling tube can be a bit of a pain to get in and lined up right.

Litttle bit tedious overall, but not too hard at all.

'bout and hour out and in.

 

[Dieseldad97]

Good luck. I replaced mine a few years back and in during the R&R invented a few new swear words. Get this...my new one is squeeking. Shit.

 

[schiker]

Done. OK it wasn't too bad after I decided to quit trying to get that agrivating $#&*@!!! rubber cover off the motor in one piece. It must be screwed on in the back somewhere under the PCM??? Anyway after ripping the cover off semi neatly the motor came out and went in ok. I was able to fit the cover back up on it and looks factory still. Unless you crawl under there and wiggle it out you wouldn't be able to tell.

I went ahead and did the resistors while I was there and its cramped and tedious. Felt like I had bent them all up trying to get them into the box hole but I guess they sprung back ok my fan is working correctly with speed controls.

1/4 drive tools and 7mm ignition wrench was needed as its tough to get to a rubber cover/pcm support screw with socket.

 

[ak diesel driver]

I straightened mine by lifting the resistor part way out to get access. Yes I can be anal.

 

[schiker]

Did not think of that. It was a bit dark under the dash. My lucky day the power company had cut power to tighten up a line down the road so couldn't use my drop light and did not have a flashlight handy. My garage has skylights and the truck was only pulled in part way to get shade on the cab. Also it was hot working without my shop fan blowing and I was getting agrivated dripping sweat all over the floor mat and seat. After I ripped the rubber cover I was disappointed in myself and wasn't in the mood to be quite as anal.


Out of curiousity I went back and looked at the motor. Its built as one piece and can't really take it apart but I banged it on the ground and blew in some holes with compressed air and as you would expect a good bit of brush dust came out. Then it worked but seemed weak. I did not compare to new one but it seemed slow. The battery I used was weak and the leads I used were just cheap alligator end test leads but it was slow to start and felt worn out. I could see through a hole and the commutator was grooved badly. Might have gotten a little more time out of it but too agrivating to change out again in a month or 3. And I like how the new one blows stronger than I remember the old one.

 

[dangerousdave]

Great Thread, thanx.