Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 06-17-2000, 12:19 PM
Backyardmechanic
Guest
 
Posts: n/a
I have a 1980 300D, the other day I was riding w/my lady and the A/C just stopped blowing cold. No power to the compressor. Tried jumping the low pressure switch to see if the Comp. would turn but no power. Removed the on/off switch inside the car(on the control panel) and no power to the switch. Fuses are good in the fuse house. Is there another inline fuse or a relay that could be causing this problem?


OK tried to recheck the fuse and all is well. As soon as I turned on the deforst the compressor did kick in. But not in the A/C mode? Still confused?

[This message has been edited by Backyardmechanic (edited 06-17-2000).]
Reply With Quote
  #2  
Old 06-17-2000, 12:35 PM
Registered User
 
Join Date: Jan 2000
Location: New Bedford, MA USA
Posts: 1,583
Recheck the fuses and the fuse holder. Eve if it looks OK, replace it. Clean the holder as well. See if this helps. If not, you've got a bigger control problem.

------------------
Jeff Lawrence
1987 300e
1989 300e
1987 BMW 325
Reply With Quote
  #3  
Old 06-17-2000, 01:31 PM
Backyardmechanic
Guest
 
Posts: n/a
OK rechecked fuses. Took test light and there is power across the fuse. Then I turned on the deforst and the compressor kicked right in. Is there some type of A/C replay under the dash or elsewhere on the car?
Reply With Quote
  #4  
Old 06-17-2000, 03:21 PM
Registered User
 
Join Date: Jan 2000
Location: New Bedford, MA USA
Posts: 1,583
If you are saying that it's working now, then you have found the problem.. Very common for fuses to be corroded and/or defective. If it's not working properly then you will have to look further. There is a control relay for the AC, but I don't know it's location for your car. Maybe Steve or Donnie can give you that..

------------------
Jeff Lawrence
1987 300e
1989 300e
1987 BMW 325
Reply With Quote
  #5  
Old 06-17-2000, 10:44 PM
Registered User
 
Join Date: Mar 1999
Location: Suwanee, GA, USA
Posts: 4,712
I would say that the ETR (evaporator temp regulator) could be the problem. Also, I don't even screw with old fuses. So many have wasted my time that I now replace them!

------------------
Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
Reply With Quote
  #6  
Old 06-17-2000, 11:23 PM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
You might have a vacuum problem. There is a compressor vacuum switch that keeps the compressor from coming on till the engine is running. It is bypassed by the defrost position. That is the basis of my suggestion.

A wiring diagram is imperative here. Got a good one at work if you still need it Monday.

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
Reply With Quote
  #7  
Old 06-18-2000, 06:16 AM
Backyardmechanic
Guest
 
Posts: n/a
OK Stevebfl, It's Father's Day so first let me say Happy Day to all you Fathers! If you have the time could you send me a copy of the schematics, I think the vac relay switch could very well be the problem.B4I forget Thanks for your help and suggestions, To all of you! Backyardmechanic, school teacher out for the summer. Will be waiting.
Reply With Quote
  #8  
Old 06-18-2000, 11:01 AM
LarryBible
Guest
 
Posts: n/a
Backyardmechanic,

I just want to point something out that may, or may not have anything to do with what you're fighting.

The ignition switch on these cars can be flaky sometimes. The one on my daughters '81 300D had to be turned back to the left slightly after starting in order for the climate control system to get a feed. I just turned a little to the left and everything would work fine. I since replaced the ignition switch, and no more problem.

Since you appear to be possibly fighting an intermittent problem, try this and see if it has any effect. It could be that sometimes the ignition switch is making contact, and other times not. This would definitely set up a variable in your troubleshooting that could drive you as crazy as it did me.

Good luck,

------------------
Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles
Reply With Quote
  #9  
Old 06-18-2000, 01:33 PM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
My scanner is temporarily out of order and I have been using my radio technicians one recently. On Monday I can send the drawing but I have just reviewed the diagram (the good one is not in the climate control book). It is in the ETM. Totally unique wiring diagrams in 78-79. They are huge 19"x15", which makes them hard to scan. They will be the same as an 80 model.

From the diagram I can tell that you must have either a bad ign switch as Larry points out, a bad fuse five or connections, or a bad compressor vacuum switch. These are the only components before the compressor on/off switch. All of this is before the ETR switch or the compressor low pressure switch in order.

There are two major vac switches one knocks out blower, the "blower master vac switch" has a green vac line going to it. The other is the compressor vac switch and it has a yellow vac line going to it. They are both behind the glove box. The defrost by passes both vac switches. They can be by-passed electrically for testing but at least the blower switch shouldn't be left by-passed as it will make the system run on low blow even when the system is switched off.



------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
1996 W201 Power Seat switch problem? Jim H Tech Help 5 07-14-2007 08:16 AM
1997 E300D Power Mirror Switch Removal indiana Diesel Discussion 2 10-05-2004 01:02 PM
Re-routing A/C line for power diesel don Diesel Discussion 2 05-23-2004 12:37 AM
a/c pressure switch question nebill Diesel Discussion 3 03-26-2004 07:13 PM
power window stopped working Lube Tech Help 3 04-01-2000 01:47 PM



All times are GMT -4. The time now is 01:56 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page