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ddparker · 10-04-2022, 10:18 PM

2014 Thor 30.1 We have been dealing with an intermittent dead short in the heaterAC blower. We have replaced the bower motor, bypassed the fuse block installing an inline fuse, replaced all the dash controls, replaced resistors for the fan speed control. Sitting idling it seems to be fine. Drive 100 ft. or sometimes several hundred miles, sooner or later it will blow. Multiple people have looked at it with no success.
Any ideas would be greatly appreciated!!

edgewant · 10-05-2022, 06:08 AM

I have a 2013 Berkshire. Not sure it’s the same issue you are having but mine would work fine then out of the blue would stop blowing air. Riding down the road would hit a bump and it would suddenly start blowing again.

My motorhome has a system supplied by Evans Tempcon. Pulled the dash cover and starting peeling back some electrical tape from a large bundle of wires that go to the heater/ac control and found a bad splice. Repaired the splice and problem was solved.

craigd853 · 10-05-2022, 11:15 AM

Quote:

Originally Posted by ddparker

2014 Thor 30.1 We have been dealing with an intermittent dead short in the heaterAC blower. We have replaced the bower motor, bypassed the fuse block installing an inline fuse, replaced all the dash controls, replaced resistors for the fan speed control. Sitting idling it seems to be fine. Drive 100 ft. or sometimes several hundred miles, sooner or later it will blow. Multiple people have looked at it with no success.
Any ideas would be greatly appreciated!!

Hello sir, sorry you are having issues. The first thing to check is to see how many amps the compressor and the blower motor are drawing. This way you can narrow down your trouble shooting. If the blower motor is pulling too many amps then you know you either have a problem in the wiring to the blower or a bad ground wire for the blower motor. Take an amp meter and a volt meter and check your power as I suggested earlier in this conversation. Once you know the amperage draws from both you will be in a better position to make a decision as to what the problem is. Also wouldnt be a bad idea to put a set of gauges on the system to see how it is reacting when running. Good luck and report back your findings

Martind4 · 10-05-2022, 01:43 PM

It really sounds like you have a direct short in the wiring somewhere. Since it's a relatively short wire run, why don't you just run a new “hot” wire(s) from the switch to the motor?

If that doesn't solve the problem, it might be the same thing somewhere before the switch.

The fact that it runs when it's not moving leads me to think the hot wire is compromised somewhere and shorting out from vibration when it get's grounded.

The compressor voltage and amperage shouldn't be a problem since this is a dash system and the compressor is probably driven by serpentine belt on the engine.

ddparker · 10-05-2022, 10:12 PM

Thanks! I will have the gentleman helping me do as you suggested. I don't do well with electrical issues!

ddparker · 10-29-2022, 10:05 PM

Quote:

Originally Posted by craigd853

Hello sir, sorry you are having issues. The first thing to check is to see how many amps the compressor and the blower motor are drawing. This way you can narrow down your trouble shooting. If the blower motor is pulling too many amps then you know you either have a problem in the wiring to the blower or a bad ground wire for the blower motor. Take an amp meter and a volt meter and check your power as I suggested earlier in this conversation. Once you know the amperage draws from both you will be in a better position to make a decision as to what the problem is. Also wouldnt be a bad idea to put a set of gauges on the system to see how it is reacting when running. Good luck and report back your findings

Thanks for your suggestions. I grounded the blower motor directly to the battery and it worked on a short trial run. We will find out for sure when we head for California next week.

Ray,IN · 10-30-2022, 11:09 AM

FWIW, over 80% of all 12V issues are the result of a poor/missing ground.

twinboat · 10-30-2022, 11:21 AM

Bad grounds don't blow fuses. They can't, a bad ground causes current to drop.

You can't short the ground side of a blower motor, it's already grounded. It doesn't matter where it gets its ground.

The problem has to be the positive feed to the motor or the motor itself.

Restrictions to the fan blade can overload the motor. Is it turning the right direction ?

What size fuse are you using ?
There are ways to tell if the fuse was overloaded or it blew from a short. A short will leave a burn mark inside the fuse, an overload won't.