Bad A/C relay again, in less than 6 months!
 

I have the same symptoms and did the same testing as I did on this thread:
http://www.peachparts.com/shopforum/tech-help/59170-300e-compressor-not-engaging.html?highlight=compressor+relay

Background:
About a week ago, it was raining really hard, I drove over some water on the road. The A/C quit working. I re-started the car and the A/C worked againg.

A couple of days ago, I started the car in the morning after a heavy rain overnight. The A/C has not been working eversince.

I have two theories:
1. Water is coming in behind the battery, where the relays are, and shorting the relay. It is raining a lot in Florida.
2. The belt tensioner is weak and the speed sensor is killing the relay somehow. Is that possible?

One thing I did not notice before, or can not remember, is when I jumped the relay with 5 and 7, the compressor did engaged but, the jumping wire was real hot.
BTW, I do have the bottom engine shield.

I do not want to buy a realy every six months. Any ideas?
:confused:

The clutch coil should take 3 amps. When they get up to about six or so they don't keep the clutch from slipping. This can do two things. First the relay don't like the load and the system shuts down if there is slippage.

Thanks Steve (once again)!
 

What may cause this condition? and more important...what is the fix?

If the clutch coil is taking more than 3amps then it is shorted/defective.

I will check into that!
 

Thanks!

I finally had some time to troubleshoot the A/C.
 

Steve or anybody else...
I guess things got worse. When I jumped the klima relay, the A/C clutch engages but fuse #7 blows within 2-3 seconds.
I measured the resistance of the speed sensor and I got .840 k ohms? between terminals # 9 and 11 (at the AC relay) and also at terminals #1 and 2 (at the compressor). The resistance of the clutch coil measured between terminal #3 (at the compressor) and its ground on top of the compressor, and it measured .5 ohms.
Furthermore, with the engine on, I checked for battery voltage at the wire to the compressor clutch, unplugged from the clutch, and there was voltage. No blown fuse. I plugged the wire and the fuse blew.
Do my readings make sense? and is it the clutch or the speed sensor?

The speed sensor won't blow a fuse even if shorted.

The clutch coil is shorted. You must replace it.

Oh well...
 

You can not win them all!:(
Thanks for the help in diagnosing...

Steve, I sent you a private e-mail.
 

Did you get it?
J.H.

Just to close this thread...
 

It was a bad clutch!:(
Steve B. ended up replacing the clutch at his shop in Gainesville.:)

Wait!...There is more to the story worth mentioning.
I live in Jacksonville, Florida and Steve's shop is in Gainesville, Florida, about 60 miles away.
Once my problem was diagnosed as a bad clutch, I called Continental Imports on Monday and I talked to Walter (Steve's partner). He was in the process of delivering a car to Jacksonville this week. After talking to him, we agreed to meet in Jacksonville after he delivered that car and take my car back on Tuesday night and work on it the next day (wednesday). We did that and I picked up the car Wednesday afternoon in Gainesville which, also gave me a chance to visit my son who is going to the University of Florida. Eventhough, they had some problems locating the part, since my compressor is a rebuilt but, they came through!
I talked to Steve while I was there. I met him before. He is a super guy (he is even nicer in person) along with Walter and their crew.
Believe me, they have a very busy shop and to provide pick up and service the very next day!!:eek: Try that at any MB dealer.;)

Kudos to Steve and the whole crew at Continental Imports! If you live within his range, go visit him. He will not dissapoint you...

For those of you wondering, the service was NOT free, they have a business to run. I am just a very satisfied customer.;)