I've replaced the blower motor resistor repeatedly. After lots of learning experiences and replacing the blower itself figuring it's drawing too much current somehow, I finally just jumpered the thermal fuse at the top of the thing to see what happens. Obviously within 20 minutes it was so hot it burned my finger.

My question is what could possibly be overheating this thing so much? The first time it happened water got into the vents and came through the fan so I installed a cabin filter which they say helps, and I replaced the fan. It didn't help. It's been getting worse over time. The first few times I'd get 6 mos out of it, and I've replaced it a few times over the past year. The last unit lasted 2 hours, the one before that blew right away.

Kevin

 

Welcome to the forum

Check the ground wire for good connection, check teh connector for good solid connections and that its not loose causing poor contact.. here is the pinout

2001 Chevrolet Impala | Impala, Monte Carlo (VIN W) Service Manual |

Connector Part Information
• 12052854

• 7 Way F Metric-Pack 280 Series (BLK)

Pin
Wire Color
Circuit No.
Function

A
TAN
63
Medium 1 Blower Motor Control

B
YEL
60
Low Blower Motor Control

C
PPL
73
Medium 3 Blower Motor Control

D
LT BLU
72
Medium 2 Blower Motor Control

E
BLK
1250
Ground

F
ORN
52
High Blower [Motor] Control

G
ORN
440
Battery Positive Voltage

 

Thanks for your help! Do you have a schematic of that circuit so I can check all the points to the relays, etc? It seems you're saying the ground may be weak, so I should check resistance at ground, not just point to point? I wonder if I should just connect gnd at pin E to a solid ground somewhere to see if it helps.

 

See if this works for you...

 

That helps alot.
It seems I get a solid connection from chassis to the pin. Shaking the wires and harness, the connection doesn't fluctuate, so it seems the ground is pretty solid. 3 ohms from the pin to a nearby chassis.
I currently have the thermal fuse jumpered, I don't have another.

1) is there somewhere I can get another thermal fuse so I don't have to buy a new assembly? I'd like to put it back in the air housing but don't want to do that with the fuse shorted.
2) Better yet is there a resettable thermal switch I can put in if this thing will continue to blow?
3) Is there some way to adapt the blower to not draw as much current? Maybe a resistor?
4) Is there some way to add a heat sink to the assembly to help dissipate the heat?

I'm trying to think of everything.

 

Have you checked out the blower switch itself.

 

In what way? I did a point to point switching it from 1-5, no shorts that I can see. How else can I check it?

Another thing is the assembly I added after replacing the blower - I did NOT put it in the vent case, I just let it hang out in the open to see how it would do. I know it needs air flow, but it seems so hot regardless. It's just that it's such a PITA to get it in there. But I will take the old one out and see if there's air flow at least, maybe the flow is blocked. Problem is if I put it in as is, if it overheats with that one fuse shorted, I'll never know. I'm not ready to risk another $35 on a new assembly added to the vent only to see that one blow. So I'll check the air flow soon as I can.