Gen 1 Light comes on when heater switch is turned on

[w5ood]

Heater worked fine this morning. After work you can turn on the heater fan switch but the fan does not come on, but the GEN1 light comes on. Any ideas? Im looking through the TM34 at the schematics just wondering if someone has seen this before. I feel like its a short somewhere.

 

[cucvrus]

Not a short. I am thinking that the switch and pigtail on the blower switch are melted and making poor contact. A common issue when the switches get older and make a poor connection. Check that out.

 

[w5ood]

Not a short. I am thinking that the switch and pigtail on the blower switch are melted and making poor contact. A common issue when the switches get older and make a poor connection. Check that out.

Ok Ive read a few things now and I see what I need to look at. Thanks for the advice. Ill check resistor and switches and pigtail.

 

[hokie8358]

Heater worked fine this morning. After work you can turn on the heater fan switch but the fan does not come on, but the GEN1 light comes on. Any ideas? Im looking through the TM34 at the schematics just wondering if someone has seen this before. I feel like its a short somewhere.

I’ve got same problem and just encountered this issues! What did you find out on your dilemma? Thanks

 

[w5ood]

I’ve got same problem and just encountered this issues! What did you find out on your dilemma? Thanks

I have not had a chance to look at it. But from what I read it sounds like it’s either the fan motor the resistor on the back of the fan housing or the switch that turns it on. I’ve looked online and all together it appears to be less than 75 bucks. I’ll probably replace them all.

 

[dougco1]

Check to make sure that mice have not nested up in the squirrel cage in your fan. You can reach up with your hand through the outside air duct on the passengers side. Pull the damper cover off and reach up to the fan and see if the fan spins. I had that happen to me, the mice packed their nest around and in the cage preventing it from turning.

 

[muttly]

I had the same issue with my m1009. Gen 1 lamp just barely glowing with fan on, I could only see it at night. A few days later the Gen1 lamp came on bright and stayed on. I found the fusible link burned for Gen 1 and it looked like it had been slowly roasting for some time. Gen 2 fusible link was questionable also so I replaced both fusible links and the problem went away. I'm not positive the fusible links caused the problem because at the same time I cleaned all positive and negative connections on the firewall. A wise man once said "if it's electrical clean it, if it's rubber replace it"

 

[hokie8358]

I had the same issue with my m1009. Gen 1 lamp just barely glowing with fan on, I could only see it at night. A few days later the Gen1 lamp came on bright and stayed on. I found the fusible link burned for Gen 1 and it looked like it had been slowly roasting for some time. Gen 2 fusible link was questionable also so I replaced both fusible links and the problem went away. I'm not positive the fusible links caused the problem because at the same time I cleaned all positive and negative connections on the firewall. A wise man once said "if it's electrical clean it, if it's rubber replace it"

I had the same issue with my m1009. Gen 1 lamp just barely glowing with fan on, I could only see it at night. A few days later the Gen1 lamp came on bright and stayed on. I found the fusible link burned for Gen 1 and it looked like it had been slowly roasting for some time. Gen 2 fusible link was questionable also so I replaced both fusible links and the problem went away. I'm not positive the fusible links caused the problem because at the same time I cleaned all positive and negative connections on the firewall. A wise man once said "if it's electrical clean it, if it's rubber replace it"

I did replace fan with a good one that I also checked before I installed it, also the resistor beside it with one tested and good!
crank truck , hit fan switch to medium speed, no fan still and gen light 1 on ! Cut switch off from fan, gen 1 light off! All alternator functioning as they should! Fuses are good, I am thinking something from heater controls themselves ! Unreal!

 

[hokie8358]

I did replace fan with a good one that I also checked before I installed it, also the resistor beside it with one tested and good!
crank truck , hit fan switch to medium speed, no fan still and gen light 1 on ! Cut switch off from fan, gen 1 light off! All alternator functioning as they should! Fuses are good, I am thinking something from heater controls themselves ! Unreal!

This is a damn nightmare lol

 

[hokie8358]

This is a damn nightmare lol

The only thing I’ve done differently in the last week. Was install a new dash pad, But I never hit any of the wiring harness or remove the instrument clusters, I did use dialectic grease on the clean terminal ends when reinstalling