Blower Motor Resistor Did not Fix Fan

[454C2500]

All, just put a blower motor resistor in there to fix my issue where my fan only works on High (i only have 3 speeds on and a digital dash). I checked the three relays on the blower motor housing and swapped them one by one with a known good relay and the same. I cannot get low and medium to work. I know I have a recirculation door issue because on high speed it closes all vents but I don't think this could be related to that. Could it be the actual switch on the dash?

 

[454cid]

All, just put a blower motor resistor in there to fix my issue where my fan only works on High (i only have 3 speeds on and a digital dash). I checked the three relays on the blower motor housing and swapped them one by one with a known good relay and the same. I cannot get low and medium to work. I know I have a recirculation door issue because on high speed it closes all vents but I don't think this could be related to that. Could it be the actual switch on the dash?

Check the dash switch, and check the positive connection on the blower itself. I had an intermittant blower, and it was the positive connector on the blower itself, which also took out the switch. You'll need to look at that connection very carefully as it can look fine when it's not. I didn't discover the bad connector until it was burned looking.

 

[HotWheelsBurban]

What year truck? I know from experience that the 96-99 trucks eat HVAC control switches in the dashboard. Pretty sure that's what it is on my Burb.... sometimes it's the connector harness gets hot too and melts.

 

[454C2500]

Mine is 1992. If its the dash switch would I still be able to hear the relays clicking? I can hear it click when I push medium and click when I push down to low. But the air will only blow on high. If there a way to replace that little rocker without replacing that whole digital HVAC display?

 

[454C2500]

Can anyone link me to a replacement dash switch for a 92? I suppose even if it is "working" by clicking the relays and changing the screen from LO MED HI it could still not be good enough to make the cut.

 

[Eveready]

If the new resistor didn't fix it then it is almost certainly the switch or a connection I would look at the connections VERY carefully before going to the trouble of replacing the switch. Be sure and come back to the thread and let us know what it turns out to be. While the newer controls crap out at twice the rate of the older ones, the older trucks (like mine) are now getting REALLY old and no telling what new tricks we will encounter.

Remember GM's intent was to design a truck that would last for three years until paid for at which time it would be traded for a new one while the old one got secondary use as a farm truck or landscape truck and finished wearing out. Instead they screwed up and produced one of the best trucks ever made and we all are reaping the benefit, but even the best starts having little failures after many years. Welcome to the forum.

 

[HotWheelsBurban]

If the new resistor didn't fix it then it is almost certainly the switch or a connection I would look at the connections VERY carefully before going to the trouble of replacing the switch. Be sure and come back to the thread and let us know what it turns out to be. While the newer controls crap out at twice the rate of the older ones, the older trucks (like mine) are now getting REALLY old and no telling what new tricks we will encounter.

Remember GM's intent was to design a truck that would last for three years until paid for at which time it would be traded for a new one while the old one got secondary use as a farm truck or landscape truck and finished wearing out. Instead they screwed up and produced one of the best trucks ever made and we all are reaping the benefit, but even the best starts having little failures after many years. Welcome to the forum.

You said it! These trucks were over engineered and we who like them have definitely done well in that respect. But circuit boards and soldered connections only last so long under the conditions most trucks are subjected to on a regular basis. Many roads in Houston, Texas area are asphalt which has not aged well(and summer heat doesn't help!). Even the concrete roads and parking lots aren't great if they are very old. All those potholes and bouncing take their toll on everything.

 

[RobMaier]

You might also look at the fuse lay out. You may have power to "switch" the relay, but the load side of the relay may have its own fuse. On my '98 the High circuit is on a completely different fuse and relay.

 

[Erin]

I have a 94 & it doesn’t blow air on low but does the other speeds. I haven’t looked into it yet. The blower has chirped for a long time.