blower only runs on slow

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Bygblok

Bygblok

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I can't find a decent schematic on the blower motor switch for my 69 Dart to find whether it's a wire, the switch or the resistor. My motor only runs on low speed no matter what the switch position is. Seems like it should only run on high if the resistor is bad. Thoughts
 
yep, the more resisters in the line the slower it goes. So... Most likely culprit is the fan switch that selects which wire/ how many resistors are employed. Or the motor is so bad it can hardly turn with any amount of juice.
 
I agree that it is probably the switch. There have been several posts on this before where people have said the "high speed" position burns out the switch. Some people have even gone the relay route (like headlights) to save the switch from high currents -- it gets complicated. Replacement switches are hard to come by. I saw one on eBay about a month ago for $99.
 
I bought a few "alternative" switches in electronics surplus stores many years ago, knowing the high current on top speed destroys the switch contact eventually.
If you open the switch by spreading the rectangular case and fingers, you could probably rebuild the worn contact face with a solder-blob, and then have THAT contact pull in a relay to feed the fan directly on high speed. I noted that GM had done exactly that in a 78 Gran Prix I owned briefly 30 yrs ago. They made a heavy gauge link from the battery to the fan with only the relay in the way for "full blast" operation.
Other speeds went through the bulkhead and variable resistances.
Check your fusebox terminal clips for the fan, too, if you have a "toasted" fan switch.
Probably heat oxidized, weakend clips.
 
Well I suppose I somehow qualify as the idiot of the day on this. I had most of the dash apart doing some repairs and I "thought" I connected the switch. Well, in a way I had, but not correctly. I ended up only having part of the connector installed on two of the switch connections.......DUH. I went back in to it tonight and found the problem and imagine this.....it works just as mama mopar designed it to. I wasn't happy with the routing on some of my repairs once I got back in so I redid that while I was there. Thanks for the help folks.
 
Many of the connectors on these old vehicles are a very easy to mis-attach. Forum might be able to help, if they live next door, or at least know that you had previously disconnected.
Remember this virtual pre-reply, "double check your work" .
 
Thanks for posting up the solution!
C
 
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