Evaporator Replacement. Wayward wire help needed. - PeachParts Mercedes-Benz Forum

timidater · #1 08-29-2004, 07:12 PM

I'm new to the forum, but have been lurking long enough to gain confidence to attempt the dreaded AC evaporator replacement on my '92 300SL. I have almost completed the job with one, maybe two problems. The picture below shows a single brown/red wire in the passenger side footrest compartment. I can't for the life of me figure out where it connects. I hope it's related to my other problem. The soft top will not raise and I get a constant light in the switch. You can hear the hydraulic motor kick on, but nothing happens. I've had the battery disconnected for the last two weeks while replacing the evaporator coil.

On a happy note, the air conditioner is now blowing very cool air! I found a replacement coil on Ebay that has a copper core which I believe will last much longer than the original. I realize that some claim copper will not transfer heat as well as aluminum, but this unit seems to be working fine and the coil fit perfectly.The best part is that the evaporator was only $50, compared with Mercedes price of over $600. Here's a link to the Ebay store I used:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7918232224&category=33547

The other picture shows my baby completely dissassembled during the coil replacement. Yes, I did replace the heater core o-rings, but went cheap on everything else. I tested all of the vacuum actuators and found none that weren't working properly, so I opted not to replace them yet. I figure I can tear the dash apart much easier next time!

The bottom of the car has been upgraded to the rest of the body color and 2003 wheels have been retro-fitted.

This has been a very difficult job, but it sure beats paying a dealer $3,400!

Thanks for any help!

psfred · #2 08-29-2004, 07:19 PM

Congrats on getting the evaporator in, it's pain.

Can't help on the wire, doesn't look familiar to me.

Peter

NormanB · #3 08-30-2004, 08:46 AM

Quote:

Originally Posted by timidater

I'm new to the forum, but have been lurking long enough to gain confidence to attempt the dreaded AC evaporator replacement on my '92 300SL. I have almost completed the job with one, maybe two problems. The picture below shows a single brown/red wire in the passenger side footrest compartment. I can't for the life of me figure out where it connects. I hope it's related to my other problem. The soft top will not raise and I get a constant light in the switch. You can hear the hydraulic motor kick on, but nothing happens. I've had the battery disconnected for the last two weeks while replacing the evaporator coil.

I have never done this job and have the deepest respect for anyone who tackles it.

However, looking at your pictures and the text I have retained here from your original post, I have this: Is this brown wire taking you for a sucker?

It may not have been connected to anything ( may be for an unfitted option) and the problems with the soft top are unrelated to this 'errant' wire.

Just a thought - and I am probably wrong!

Good luck in sorting out - I am sure you will!

timidater · #4 08-30-2004, 10:19 AM

Thanks, Norman. I plan on entering diagnostic mode tonight and looking at the trouble codes. When I move the car, I get the warning tone that the top isn't locked. It's probably related to a limit switch not getting made.

Thanks,

Tim

G-Benz · #5 08-30-2004, 01:37 PM

That brown/red wire is a ground connection. It could possibly connect to a feature not available for your model, but being an SL, what options weren't?

Check around one more time for a similarly colored wire.

If your top worked prior your de-install you probably need to resync the top operation...this will always occur if you disconnect the battery for an extended period.

It may take several tries up/down tries to get it working right.

Disconnect the battery once again, reconnect after a few minutes and try again...

timidater · #6 08-31-2004, 01:12 AM

Thanks, G Benz. I tried disconnecting the battery several times with no success. After that,I didn't have time tonight to do anything but put the hardtop on to see if that would help. The hard top locked down and I stopped getting the light in the switch and the rolling alarm. However, I can't fully release the hard top. The front releases, but the back remains locked. Oh well, hopefully I'll have more time to mess with it tomorrow evening.

Thanks,
Tim

timidater · #7 09-02-2004, 09:53 AM

Success! After checking the diagnosic codes, erasing and reading the codes again, the problem was isolated to the left front top lock circuit. I used Alldatadiy.com to locate where the wire connection points were and noticed the wire was tight where it went into the roof pillar. It turns out that a wire was pinched and grounded out. Everything started working when the wire was freed.

As for the stray wire, the only reference to a brown/red wire I could find was for the power antenna. Makes sense that it's hanging loose since the car has an aftermarket radio.

Thanks,
Tim

NormanB · #8 09-02-2004, 10:09 AM

Hey well done Tim - you are the man!

I thought that stray was taking you for a sucker!

Respect.

Zeus · #9 09-02-2004, 11:24 AM

You are a brave man indeed - well done!

The heat this summer almost - almost - made me attempt the same repair on my 300E. However, fall is upon us and the air is cool. I'm putting it off another year...