Yet another blower malfunction thread

[hugho]

Wel a month or two ago my htr blower on my 1998 Tahoe started to whine when it was especially cold here in subzero Wyoming. About this time I noticed that only the high position worked.. So I went to Carquest bought a new blower.
But the blower still only worked on high. I read the threads here and did the complete diagnostic including looking at the resistors, testing for current here and there and I finally concluded that it had to be the switch. Fuses OK of course. popped in the new blower switch(from carquest) and it could only go in one way. Bingo. all the speeds worked........but in reverse!!! In other words the low position was low, the next speed was high, the next medium and the next to last position was low and the last position was wide open as always. I figured some Chinese teenager had reverse wired it but whatever. I relabeled the switch speeds. All has been well for 6 weeks and today my wife said only the high position works. I wonder what gives. Do I dare throw another switch in? The wires looked OK. Fuse #12 is fine. I'm willing to replace it from another supplier like NAPA or Rock auto but I am puzzled. Any ideas???

 

[sgtpoliteness]

If only the highest speed works, that's the resister pack. The blower gets the full voltage at that speed and doesn't need resisters to slow it down. And I would replace the fan control, the one the Chinese toddler soldered together. =)

 

[hugho]

If only the highest speed works, that's the resister pack. The blower gets the full voltage at that speed and doesn't need resisters to slow it down. And I would replace the fan control, the one the Chinese toddler soldered together. =)

thank you. I was running out of ideas. I replaced the htr switch some poor 12 yr old girl built with a new one from rockauto probably built by her sister and still nada ...the hi is still the only one working so I'm only left with the wire resistors. Unfortunately they are VERY hard to access because the air bag is in the way and only a few inches of clearance. and you have to feel blind for the screws. so back to it.......

 

[sgtpoliteness]

Good luck!


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[sgtpoliteness]

Did you replace the resister pack??


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[hugho]

Did you replace the resister pack??


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Yes I replaced the resistor pak, against my better judgement after I did a cursory visual inspection. So Now I have installed 2 new fan switches, a new resister pak and a new blower motor and still only the high works. The only thing I can think of is the harness. I jumppered the hot connection in the harness to the other 4 pins and can get no fan activity. The harness looks perfect at the resister end and the switch end, no sign of overheating. We must be missing something real obvious. What is it?