The 12v+ supply wire is Hot (temperature) - Early AC

[vanis13]

this is a request of what to check an how.

while fixing what turned out to be a switch issue https://www.thesamba.com/vw/forum/viewtopic.php?p=10075722#10075722

I noticed the supply wires to the fuses are hot. The 25A fuse that powers the evap blower was so hot it melted the fuse holder. the wire from the battery+ terminal is also hot on the battery side.

I've learned that voltage drop is a thing on starter issues so I tested and I see a bit of a voltage drop between battery and fuse(s).

Thinking a new/bigger wire between there may be a solution...But then I'm thinking it was spec'd that way by VW ad they typically do a design job good job, maybe it's the blowers or resistors that I may want to check for resistance or something.

the Evap blower relay (the left one in the schematic) gets hot. the load wires in/out of it are hot.

the radiator blower relay doesn't get hot. only the incoming load wire is hot, not the outgoing.

I've tried different relays and get eh same behavior.

What kinds of tests could be most fruitful at this point?

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83.5 Westy with Subaru 2.5, 4 spd manual, center seat, COLD A/C on 134a!, Winter camp heated with an Espar B4 gasoline furnace

www.SuperVanagon.com - some stuff I make

[xflyer]

Post some photos of the AC. Specifically the evaporator. What year is the Vanag
on?
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1989 Campmobile, 1984 7 passenger beater Vanagon
Both with cool A/C

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From the web:
"If the fuse itself has not blown, but the fuse holder melted, it indicates that the fuse holder was making poor contact with the fuse. Loose connections are common with poor quality fuse holders."
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82 westy
w:
2.5 JDM Subie
Rear discs

[vanis13]

[vanis13]

[xflyer]

Photo will show which maker of AC you have. I had a 78 pop top with AC. Was either DPD or VPC, not important in that case. Had chronic trouble with main AC fuse getting hot and failing until followed a suggestion to replace the fuse and its holder with a circuit breaker. As used on American cars. No problems after that.
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1989 Campmobile, 1984 7 passenger beater Vanagon
Both with cool A/C

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[vanis13]

[xflyer]

Is the evaporator above the rear seat/bed?
Think you should try the circuit breaker in place of the fuse. On my 89 which has "VW Factory" AC the main fuse, 50 amp metal strip type in the left rear pillar, got hot enough over time to melt the plastic on the fuse/relay panel it was mounted to. Replaced it with a fuse holder I found at the FLAPS and a larger version of the typical plug in, two prong fuse. That has worked well for 20 yrs. Others have reported that same problem. VW probably thinks its OK as it lasted over 12 yrs till failure.

https://www.oreillyauto.com/detail/c/littelfuse/li...&pos=6
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1989 Campmobile, 1984 7 passenger beater Vanagon
Both with cool A/C

[djkeev]

Do NOT assume VW over designed any wire on your Van!

I'm here to tell you that they did not and that they "cheaped out" as much as possible on wire size and design!

There is often massive room for improvement using increased wire size and relays.
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[xflyer]

The AC in question is not a VW design. Its a USA made aftermarket kit. Sometimes dealer installed or farmed out to an AC shop. Those fuseholders in the photos are notorious for poor connections over time.
Also installing a relay in the engine compartment, for the compressor clutch can take some of the electrical load off the wiring. It takes about 1/2 amp to close the typical relay. The clutch draws a lot more than that. Consider the length of the wiring from the front back to the compressor.
https://www.busdepot.com/141951253b

Or use this kit: https://www.busdepot.com/wr1
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1989 Campmobile, 1984 7 passenger beater Vanagon
Both with cool A/C

[vanis13]

[vanis13]

[vanis13]

[vanis13]

thank you @jimf909 for suggesting this DC Amp meter I just got a couple days ago. that makes these readings possible

from this thread https://www.thesamba.com/vw/forum/viewtopic.php?p=10072354#10072354

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[xflyer]

" 2.4a in the wire that activates the AC clutch. measurement taken at AC compressor"
What might be difficult to measure is the initial pull in amp draw when the clutch engages. Depending on ambient temp, the clutch could engage and disengage every few minutes. That's some load that can be taken off the wiring and fuse(s) with a relay.
And, as I mentioned, those molded fuse holders in the photos are notorious for poor connections. That means resistance which turns the circuit into a heater. Cut the wires, either side of the fuse holder. Crimp on the appropriate connector for the circuit breaker and hook it into place.
Also what I mentioned about the AC on the 78 keeps coming back in my mind. There was constant trouble with the fuse that was part of the original installation. Fuse would get hot and cause the fuseholder contacts to get weak. That meant more resistance and more heat until the fuse itself failed. I was quite skeptical when the suggestion came about the circuit breaker. Since the breaker was (is) not expensive, I gave it a try. As mentioned the AC worked fine for 10 yrs after that till I sold the van.
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1989 Campmobile, 1984 7 passenger beater Vanagon
Both with cool A/C

[vanis13]

[vanis13]

[shagginwagon83]

Does those clamp multi meters work with DC current?

Let me know if you need some data points. It might be next weekend until I get my system put back together.

Maybe your fan is going out and pulling a large draw to compensate. I hope that isn't the case because I can't find them anywhere online.
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Brandon
"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram @joannthevan