A/C Wiring Issues

HB Chris

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I hate dealing with wiring issues but I understand the schematics fairly well. For unknown reasons my A/C fuse will blow, after one hour or ten minutes or sometimes when I simply turn it on. I have checked every wire in the console, the switches, the wires to the relay and the compressor. I thought it was the fan clutch but power from the battery clicks it open and close. Thought I might have a grounded wire in the console, nope. I removed the fuse and searched for grounds from the load side of the terminal, nothing. Sometimes it seemed to work with compressor disconnected but that isn’t it. I have spare e3 blower switches (too short for e9 faceplates) to compare, but everything is working now. I know after I put it all back together it will blow again, but when is the big question. The e9 blower switch gets hot on the back sometimes but not every time. No spares of that one. I have an e3 spare if someone needs one and spare temp switches again if someone needs them. And I have chrome bezels but they don’t fit either switch or the Blaupunkt and they look identical, go figure. Most temp switches are SAE thread I believe now, extra fine and the metric bezels are also extra fine thread pitch. Time for a beer.
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Stevehose

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Is the compressor clutch or fan motor causing an occasional high load/resistance and blowing the fuse?
 

HB Chris

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Steve, I don’t know how to test for that. I originally thought it was clutch as disconnected everything else worked but now all connected everything is working. The clutch is 5 ohms which anything over three is supposedly good.
 

Ohmess

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Hi Chris -- two things: check the resistance of the fan motor. Your problem may be in the armature wiring of that motor. If you are using the stock fan, I have one and could provide a reference value for you (and you can have it if you want it).

I would be interested in acquiring one of the longer neck e3 switches with the associated bezel (and yes, they are SAE threads). I read elsewhere on the forum that the switches are different, but the neck can be swapped. It was very difficult to install my switch onto the gauge plate I made because of the thickness of the vinyl I used to cover the plate. If ever I disassemble that baby, it will be very hard to get the switch back in and I would love to have a backup plan.
 

HB Chris

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Hi Chris -- two things: check the resistance of the fan motor. Your problem may be in the armature wiring of that motor. If you are using the stock fan, I have one and could provide a reference value for you (and you can have it if you want it).

I would be interested in acquiring one of the longer neck e3 switches with the associated bezel (and yes, they are SAE threads). I read elsewhere on the forum that the switches are different, but the neck can be swapped. It was very difficult to install my switch onto the gauge plate I made because of the thickness of the vinyl I used to cover the plate. If ever I disassemble that baby, it will be very hard to get the switch back in and I would love to have a backup plan.

The e3 fan switches are short neck, do you want one of these? The temp switch is SAE thread for sure.
 

Markos

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Hi @HB Chris

I have a spare switch (temp or fan) that you can borrow for diagnostics (and until your source a replacement). I need to keep them but I don’t need them at the moment. If it helps I can test them first but will need some input from the forum on that.


Side Note:
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Also, the hole in the AC face plate is quite large. This means that the collective can look into a threaded brass adapter sleeve for e3 switches. That is, if the e3 post is long enough to hold the knob securely. I will check this evening, as I have both types. The sleeve only needs to be long enough to catch the threads on the face. These adapters could be made very quickly and cheaply with 2 taps and die. Tap the inside of the brass tube. Use a die on the outside of the sleeve. Use a tap on the inside of the chrome jam but.

The enlarged the round chrome “jam nut”would be invisible, hidden behind the knob. Also, the jam nuts are still available. I think it is the SAE version, but it doesn’t matter due to being tapped.

Food for though, a quick theory to debunk and all do the tools (and possibly the tube) are available at Ace Hardware.

This is a 3/8 OD (1/8 IPS) brass lamp nipple:
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