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Running a 300SDL WITHOUT the klima relay

1987 300SDL 240,000 miles. My wife had the unfortunate klima relay failure while driving down the highway. The AC compressor began to seize up -- the clutch was very engages, and the serpentine tore itself to shreds after she accelerated after a tollbooth. For a long time the AC hasn't worked and we don't care. But she was some bummed to be trapped in 95F in the sun waiting for AAA -- the towtruck operator took pity and replaced the belt (I had a spare in the trunk) but didn't fix the real problem: a stuck clutch on a frozen compressor. She made it home with the belt riding hot over the stalled compressor pulley -- I can't blame the new belt, it got her and the kids home over 100 miles of varied driving. The belt sizzled when I pushed it with my finger.

So the next morning I go out to see what's up -- I start the car and immediately see (and hear) the compressor laboring and spinning the clutch and pulley much more slowly than the other accessories on the belt.

I pulled fuse #5 to see if I could free the clutch -- and it immediately let go and the care breathed a sigh of relief as the stuck compressor was loosed from the clutch and pulley and the belt began to spin properly on the unclutched pulley. I put fuse #5 back in, and the clutch remained still unstuck, a good thing but puzzling.

I removed the KLIMA relay after reading a bit. I don't want AC. If I could, I'd take it right out of the accessory belt path and use a shorter belt, but before I go that far I want to disable the clutch so that it /NEVER/ siezes up again. I wonder if I can run the car without the KLIMA relay. Any thoughts? I'd like to just leave the KLIMA relay out so the clutch /NEVER/ gets juiced and locked to the frozen compressor again....

Any thoughts would be appreciated.

Reply to
mdibiofuel
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Can the clutch's electrical connection be disconnected at the compressor?

Reply to
-->> T.G. Lambach

On Jul 31, 2:47 am, "-->> T.G. Lambach

Reply to
mdibiofuel

Shine a good flashlight on it and you should see it... should be on the top in the front....

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Reply to
Tiger

Unbelievable, that says something about how tough the serpentine belts are - to go 100 miles without it buring out - incredible!

Reply to
rpffreeman

Interesting. The Klima relay is designed to prevent what you experienced: a seized compressor clutch.

The Klima relay works by comparing the engine and the compressor speed. It is supposed to cut out the clutch in your situation. I cannot explain why it did not.

I would prefer the suggestion from others: disconnect the clutch connector which is a 3-wire connector on top of the compressor just after the pulley.

I have not checked the ETM (Electrical Troubleshooting Manual) yet. My memory says that the engine speed goes through the Klima relay. If the relay is disconnected, the obvious difference is no tachometer reading but there may be other control based on the engine speed. There is no mechanical problem but the emission (e.g. EGR) and performance may be affected.

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Reply to
Wan-ning Tan

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