Blower works on high only

[PrairieDrifter]

In 99% of cars if your fan works right only on high, It's always the resistor block. Make sure to check the harness for the resistor block as well. 90's to late 2000's chevys always melt the resistor block and connector.

 

[AuroraGirl]

Probably a resistor failure. You could diagnose it, or just put another one on it. In this case, I don't think anyone would judge you for just throwing parts at it, because it's cheap and usually the culprit.

A visual inspection is a must though. Check the blower fuse and look at the resistor connector for any melting or burning.

I can smell the dodge dakotas from here

 

[Raider L]

Usmczo6,
My fan only being on high fan speed problem has always been the switch. Since I've had my truck and had that problem it was the switch. When I removed all the A/C from inside the engine compartment and removed the fan speed relay, the thing with the curly wires, is that what ya'll are calling the "resister"? I only knew it called the speed relay. I had to find a new place to put it, but where. I still have the factory original relay in the truck and installed it in one of the ducts under the dash attached to a piece of plexiglas. I can look right in at it in the duct, I had to saw it off and shorten it when I was removing the duct from the drivers side under the dash. The two or three times it would only run on high I replaced the switch. A few years later it would go out again and I would replace the switch and everything would be back to normal.
And like you found out when one of those curly wires burns, that to. But what caused the wire to melt? I know those wires get hot because they are carrying current all the time, well whichever one the switch is on.

And for the choke? Get a manual choke. That eliminates any problems from the electric choke and you can control the rpm anywhere you want it to run on those cold mornings. Most of the older carbs. have some accomodation for a manual choke. Or you can get a kit to attach it.

 

[My78truck]

Okay, a little late getting in on this discussion. My selector assembly blower switch was working. Then it wasn't. I unhooked negative on battery and pulled the power connecter on assembly and went and had some coffee. Came back and hooked the power connection back up (after cleaning contacts and painting with some dielectric grease) then reconnected the battery. Viola, working. Went out today, turned on ignition and then flipped the blower switch, not working!!!!

This is a 30+ year old assembly. So, should I just bite the bullet and replace the entire assembly (79 + shipping), or buy pieces and parts.

Thanks

 

[AuroraGirl]

I rigged mine by putting in an on off switch amd retaining the speed switch. The speed switch sometimes needs to be wiggled or toggled to work. Old. It acts weird when it acts up. My wires were seized up and the control head broke its levers so I didn’t have anything to replace it with. I have an ac truck unit but I couldn’t figure out how to make it work. Maybe I’m dumb. But I have sinced unsexiest the lines amd eventually will replace the lever head thing.

 

[Snoots]

Nah. I wouldn't start throwing $$ at it. Since you made it work before, go back and check ALL of your connections.
Ignition on (truck not running):
Fan
resistor assembly
relay
switch

 

[Corvette Ed]

I agree with Snoots,you have a connection problem.

 

[AuroraGirl]

See the fan switch? Mine constantly needs to be wiggled because the fan will behave erratically or not behave at all

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[Snoots]

That's the same switch I just had to replace 2 weeks ago. Got a new one from USA1. $28 including s&h but well worth it.
The old one refused to be rebuilt.

 

[Raybo135]

Sounds like a bad blower motor resistor. Here’s a link to an example one.
The “squealing” is usually a dry bearing on the motor. Easiest fix is just replace the motor.
Good luck.

Where is this Resistor located on a 73-78 K10? I have never seen this before and I have been around a 76 K10 since 1976. My switch just never went out before. But now it has and I needs the full speed for the A/C. Thanks for any assistance you can provide! ! !

 

[75gmck25]

Lower speeds use the resistor pack, which is mounted in the plenum under the hood. High speeds use the blower motor relay, also in the plenum, and a 30 amp fuse that is inline with the blower power feed wire that runs across the top of the firewall. If you only lost high, it’s probably that in-line fuse. All of these items are under the hood, so usually there is no need to pull the dash apart.

 

[Charlie]

If yours is similar to mine, here is the fuse for fan high speed and resistor.

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[75gmck25]

Good picture. And the sliver box right below the resistors is the blower relay.

On my truck that 30 amp fuse started to overheat and it melted the fuse holder. I replaced it with a 30 amp blade fuse and holder and its never been a problem since.

 

[Charlie]

Mi

Good picture. And the sliver box right below the resistors is the blower relay.

On my truck that 30 amp fuse started to overheat and it melted the fuse holder. I replaced it with a 30 amp blade fuse and holder and its never been a problem since.

Mine went out 2 years ago. Fuse holder burnt. Replaced with same type and no more problems. I also deleted the low speed fan by removing the top wire from the resistor connector. Now I have 3 speeds and the low position is off. Works great.

 

[The88]

Same issues here. Subscribed!s