94 Suburban rear blower not working

[tammyiam]

Heh everyone,
I have a 94 Suburban that I dearly love. It has over 200,000 miles on it and is still running great. But she has a couple little problems, they may even be connected. I had mentioned these on here before, but none of the suggestions I received fixed them. So I will try again, this past summer the rear air just quit working. One day it worked the next day it didn't, no big deal it's winter, won't need the air anyway right? Wrong, the rear heater isn't working either. I should say the blower is not working. I took the blower motor out and hooked it directly to a spare battery I had sitting around and it ran fine. I don't know if this matters, but I hooked the hot to the positive and the cold to the negative battery posts, and I laid it on carpet, so it was not grounded. I put it back in, and still no blower. I was told by the dealer that if the blower motor worked that way that was not the problem, and more often than not it was the relay. They said that I should replace the relay in the rear (the one with the little coiled wire on it) so I did and still nothing. I hooked up a volt meter and got almost 13 volts, this stayed the same no matter what position the switch was in. So does this mean the switch is the problem? Is there a way to test the switch without going and buying a new one like I did the relay? It is also my understanding that the switch in the front overides the rear one, so if the back one were bad, it would still work using the front one. But if the front one is bad neither of them would work. I just don't understand why if the motor is getting voltage no matter what the switch is on shouldn't it be running all of the time instead of not at all?

Next at about the same time that this happened my max switch in the front dash to recirculate the air started acting funny. When you hit the switch you hear a change in the flow of air. When you have it on dash air blowing on any speed, you can hear the air flow change, and it nearly stops coming out of the dash vents, but it doesn't start coming out anywhere else. Any idea what could be up with this, and could this be connected with the rear air problem. I will be honest, the kids and grandma say they are freezing in the back, and I am so broke especially with Christmas coming that I can't afford to take it to the dealer again. Any help would be greatly appreciated.

Thank you,
Tammy

[sub006]

Something is preventing current from getting to the rear blower. You replaced the relay, so I'd suggest checking the fuse (in the block under the dash, owner's manual will show which one) and then the dash switch. After that, try running a separate wire from the dash switch through the interior (over the seats) to the rear relay. If the blower turns on, there is a short or break in the factory wire.

As for the control of air flow through the vents, I believe this is done with flaps undr the dash. I think they work on vacuum (note the hiss when you move the dash lever), but I have not personally worked on this area and don't know for sure.

The best auto electric shop in my area will diagnose anything for $75. When you're stumped, it can be worth it. Once you know what to repair or replace, the job becomes straightforward.

I have a '90 with 384,000 miles. Anything can happen once you get well into six digits. But these are relatively simple and rugged trucks; don't give up!