Why does My Heater Work And Not On Medium Speeds?

[uglytruk]

The high works, but medium comes and goes. I wiggled the resistor, no diff, but wonder why it comes and goes at it's own liking?

 

[dyeager535]

Good timing.

http://coloradok5.com/forums/showthread.php?t=245590&highlight=heater

Hope that helps. Does wiggling the switch, or SLOWLY moving it between the speeds get different fan speeds? I noticed I could "force" mine to work if the switch was held inbetween the detents sometimes.

 

[uglytruk]

I don't believe wiggling it works. It comes and goes at will... I'll check the link, thx...

 

[dleroy43]

hmm mine works on low and med but not high, we should get them together

 

[uglytruk]

Hi is usually the large wire on the relay at the heater core/fan. wiggle it...

 

[bobby2114]

mine did the same thing. it wouldnt work on any speed but high. high went out one too after 6 months. it was the switch on the heater controls

 

[chevyuser74]

blower resistor

 

[GEORGIA GABE]

blower resistor

x2... its the silver thing attached to the ac box next to the fan. There is a purple wire that attaches to the fan itself, follow it back 6 inches and that silver thing that it is plugged into is what you need to replace.

 

[uglytruk]

Nope, sorry guys. I wiggled the cut up wiring harness behind the engine, and the fan started on medium. So when it warms up, I'll remove the air cleaner and find the loose connection. BTW, I had wiggled the resister wiring. Connections where clean and tite, and then I jigggled the harness mentioned above... Voila...

 

[dyeager535]

Yeah, you'd need to check voltage at the wiring connector at the resistor...if there's no voltage there, you'd see exactly what you found. This is why you have a voltmeter. These electrical systems are typically VERY easy to diagnose with a voltmeter.

Or, in your case, are able to wiggle the wiring and find that the condition changes.

 

[uglytruk]

I can live with the intermittent med speeds, and it's windy and 30f now, but going down below zero tomorrow... sheesh...

http://www.youtube.com/watch?v=0Z_Dl8n-K1E&feature=channel_page