'97 GMC Safari HVAC only operates on speed #2

mchan68 · July 6, 2010

Okay, I'm not sure where else to post this, so here it goes:

On the vehicle listed in the thread title, the blower speed works only on #2. Speeds #1, #3 and #4 are inop.

I plead guilty to jumping the gun in calling a blower motor resistor. Replaced the reistor new from GM, and the same thing happens. Speed #2 is the only speed working.

Without a wiring diagram available, I checked the wires on the blower motor resistor connector and found good V-BATT on the thick red and thick black wires. There are four colours, light blue, orange, yellow and beige. The same four coloured wires are on the back of one of the HVAC control head connectors, which happens to be an eight wire connector (of which four are identically coloured to the resistor connector in the engine compartment). Orange, yellow and beige check out. Light blue appears to be open. So I overlay it, and now restore function on speeds #2 and #3.

So, as things now stand, I have managed to restore function on speeds #1, #2 and #3 with the new resistor plugged and the light blue wire overlaid (only #2 and #3 work with the old resistor plugged in and light blue overlaid).

I "borrowed" another HVAC control head off another used vehicle of similar model year with the same result (this one works on speed #4). Is there anyone here, who is familiar GM HVAC systems? Vehicle is a manual A/C system if it matters, by the way.

This is exactly why I hate working on off-make vehicles Posted Image

Bruce Amacker · July 6, 2010

I can't say I'm familiar with the system but I have Mitchell OD if you need skis or diag info.

Posted Image

Bruce Amacker · July 6, 2010

Try this:

Bruce Amacker · July 6, 2010

And this:

mchan68 · July 7, 2010

First of all, I would like to give Bruce a HUGE thanks for the PDF files. They helped a lot. It turned out that speed #1 was due to an open in the resistor itself. But to restore function to speeds #3 and #4, I had to repair a corroded connection between the resistor and the control head under the main battery junction box. I wish there were more I could contribute to this forum to assist others. A special thanks goes out to Keith as well, for providing us with this venue!!! Posted Image

Brad Clayton · July 8, 2010

Quote:

A special thanks goes out to Keith as well

Well he is a "special" guy. Posted Image

Keith Browning · July 9, 2010

Hey! I didn't do anything!!!

LARRY BRUDZYNSKI · July 9, 2010

Aaron · July 10, 2010

I'd have glued the knob for the fan speeds in that position, then carefully scraped off the 1, 3, and 4 numbers on the dash.

It only has one speed now.

And that speed happens to be called '2'.

Fuckin' 97 safari... Mike how do you end up with all the good jobs?

mchan68 · July 10, 2010

I'd have glued the knob for the fan speeds in that position, then carefully scraped off the 1, 3, and 4 numbers on the dash.

It only has one speed now.

And that speed happens to be called '2'.

Thanks Aaron. I nearly fell of my fucking chair after reading that!!! I sure could use a good laugh after the hooping I've been taking this week, in 40+ degree heat.

Originally Posted By: Aaron

Fuckin' 97 safari... Mike how do you end up with all the good jobs?
Well. Here's the way it works. In our shop, they have what's called ERO, which I'm sure most of you guys are well familiar with. This system is supposed to preclude a tower operator. However, politics being the way they are in every shop, there's going to be guys that are the ones flagging 20 hours a day banging off ball joints, brakes and #3s and #4s all day long with little to no certs. While poor bastards like me (and again I don't proclaim to be a 'good' tech by any means), locate to whatever job happens by.

But here's the thing. Our tune-down guys commented, asking how I got the job, because it's "electrical" work. However, if I were to refuse the job ("stick handle" I believe would be Aaron's terminology), I would be labelled a "pick and chooser". So WTF? I can't win either way. Yes, it did take a little digging on my part, due to the fact that I haven't wrenched on any off-make stuff in a coon's age. But the outcome still resulted in a successful repair, which is all that mattered to me in the end, without me losing too much. The customer happened to be a "friend" of one of the service advisors, if it matters.

LARRY BRUDZYNSKI · July 10, 2010

Mike, I applaud your efforts Posted Image

Even if the stiffs in your shop give you a hard time, you my friend...dealt with a difficult situation that your not familiar with and dealt with it, successfully by the way it sounds. SO SCREW THEM!!!!!! Posted Image

Aaron · July 11, 2010

I'd have gone in on saturday and taken a shit on that tuneup guy's toolbox lid.

mchan68 · July 11, 2010

I'd have gone in on saturday and taken a shit on that tuneup guy's toolbox lid.

An open empty bottle of friction modifier under the toolbox, buried right up against the wall would probably be more effective.

eastendpowerstroke · July 12, 2010

A drizzle of that friction mod on the collar's of all his fresh from the uniform company work shirts is an option too........

Posted Image

BTW new friction mod smells bad, but old used and burnt gear oil/friction mod smells REAL BAD....

LARRY BRUDZYNSKI · July 12, 2010

Less than a buck for a can of anchovies cracked open for a few days.....REALLY BAD SMELL.... Posted Image

Aaron · July 13, 2010

Yeah, but they probably work in the same shop, Larry.

LOL

If you squirt about a half bottle into each of his workboots, it'll start to burn by about 10:30... feels kinda like really bad athlete's foot, but everywhere, and all of a sudden. Posted Image

LARRY BRUDZYNSKI · July 13, 2010

mchan68 · July 13, 2010

If you squirt about a half bottle into each of his workboots, it'll start to burn by about 10:30... feels kinda like really bad athlete's foot, but everywhere, and all of a sudden.

Hmmmmm. And just how in the hell would you know this? Posted Image