pic, what relay is this next to the Klima relay that controls the compressor - PeachParts Mercedes-Benz Forum

ray m · #1 07-23-2008, 03:32 AM

pic, What relay is this next to the Klima relay that controls the compressor. My compressor wouldn't switched to 134r freon,new dryer and evaporater and compressor. Jumped compressor from +on battery and it worked. Jumped the low pressure lines together and no engagement. I pulled a 10a fuse from this relay, and put a 15a cause that was all i had, and the compressor came on and worked for a day. What function does this relay have . also in what relation to the compressor or Klima. Today I changed it to a 7.5 fuse just in case the 15 is why it stoped again,maybe shorting the Klima. Any thoughts on the circled relay in the attachement. 1985 300sd 126

brandlj · #2 07-23-2008, 09:37 AM

There is no picture in the thread. I am assuming you are talking about a silver relay with a 10A fuse in the top of it????
If this is what youmean that is the OVP relay. Overvoltage protection relay. It protects many things in the car from too much voltage, like your ABS brake computer.
Only a 10A blade type fuse should be used in it. Is your ABS light on?

ray m · #3 07-23-2008, 10:37 AM

Quote:

Originally Posted by brandlj

There is no picture in the thread. I am assuming you are talking about a silver relay with a 10A fuse in the top of it????
If this is what youmean that is the OVP relay. Overvoltage protection relay. It protects many things in the car from too much voltage, like your ABS brake computer.
Only a 10A blade type fuse should be used in it. Is your ABS light on?

I dont know what happened to the pic but here it is now. Sorry all. Ray M

ray m · #4 07-23-2008, 10:47 AM

Does it control anything else besides the compressor and the ABS brake computer. I hope I don't have to chase anything else down in the car. Is it possible I blew that fuse or the klima when jumping the compressor to the + terminal on the battery to see if the compressor was working.

brandlj · #5 07-23-2008, 11:45 AM

I will check my wiring diagram tonight when I get home and see what else it protects unless someone else chimes in before then. I know that on my 85 380se gasser, it protects the ABS computer, the idle speed computer and the fuel injection computer.

compress ignite · #6 07-23-2008, 07:13 PM

And the Climate Control Unit (Push-button) [A/C's Brains].

When you said you, "Jumped the Compressor",from the," + (I assume Positive)
on the Battery", ...Specifically (VERY important) Where did you apply the
12 volts Positive [To which WIRE or TERMINAL] ? If you put the 12V to
anything OTHER than the positive pole on the compressor (OR IT's WIRE)
you may have trouble.

That positive pole on the Battery is not what it seems...look at it as a direct
connection to LIGHTNING.Everything in the engine compartment is negative
ground and all it take to un-leash havoc is the threat of a POSITIVE connection.