Where does this wire go? - PeachParts Mercedes-Benz Forum

Ether · #1 05-07-2012, 03:47 PM

Can anyone tell me where this should go? The wire from the temp sender shown in the picture is broken and I can't determine where it was connected. This is on my 80 SD.

kerry · #2 05-07-2012, 05:05 PM

There are two senders and two wires in that photo aren't there? Neither of them look broken to me.

sleepstar · #3 05-07-2012, 05:35 PM

the wire for the EGR thermo valve? leave it disconnected haha

Dr. Sternschnuppe · #4 05-07-2012, 05:55 PM

Dr. Sternschnuppe · #5 05-07-2012, 06:22 PM

Ether · #6 05-07-2012, 11:06 PM

Quote:

Originally Posted by kerry

There are two senders and two wires in that photo aren't there? Neither of them look broken to me.

Bad framing on my part Kerry. The wire from the temp sender next to the EGR temp sender is the one that's not connected. There's maybe 15" - 18" of wire on it. It may have been this way for a while but I happened to notice the wire hanging loose a while ago and in trying to re-attach it has me scratching my head. It doesn't seem to be long enough to connect to anything.

kerry · #7 05-07-2012, 11:15 PM

It's been a while since I looked at my SD but I think that wire may have gone to the auxilliary fans?

Ether · #8 05-07-2012, 11:18 PM

Quote:

Originally Posted by Dr. Sternschnuppe

Dr. Sternschnuppe,

Is the "Temperature Switcher (100 C degrees)" functionally part of the EGR circuit? If so, then this is not an issue as the EGR has been non functioning for as long as I've owned the car (11 years). Or, is this the 100 C switch to turn on the Aux fan? Might explain the warmer than normal operating temps I've been experiencing.

BTW, that photo is about a month old. I've since, finally got around to installing a non EGR intake manifold that I had purchased several years ago and deleted the EGR hardware all together. Here's a new pic.

Ether · #9 05-07-2012, 11:24 PM

Quote:

Originally Posted by kerry

It's been a while since I looked at my SD but I think that wire may have gone to the auxilliary fans?

That's what I'm thinking, but I can't seem to match the end of the wire to a connector or another wire. Need to dig up a wiring diagram (with English descriptions

) and noodle it out.

kerry · #10 05-07-2012, 11:47 PM

Is there a wire hanging loose from the fan on the top right somewhere?

Dr. Sternschnuppe · #11 05-08-2012, 09:16 AM

Quote:

Originally Posted by Ether

That's what I'm thinking, but I can't seem to match the end of the wire to a connector or another wire. Need to dig up a wiring diagram (with English descriptions

) and noodle it out.

See USA MY 1981.

kerry · #12 05-08-2012, 09:29 AM

I don't see any wiring diagram for the auxilliary fans in that pdf.

Ether · #13 05-08-2012, 10:36 AM

Perusing the W116 Service Manual at W116.org I see that the 100 C coolant temperature switch when closed will provide ground to the coil of the Auxiliary Fan Relay. The Receiver Dryer Temp Switch is in parallel and will also activate the Aux Fan Relay.

http://handbook.w116.org/ETM%5C80SD.pdf

So, if that is indeed the 100 C switch then I just need to locate the Aux Fan Relay, or the wire leading to it.

If the temp switch in the middle of my photo is the 100 C Aux Fan switch then what is the sensor on the other side of the thermostat for?

tangofox007 · #14 05-08-2012, 11:01 AM

Quote:

Originally Posted by Ether

...then what is the sensor on the other side of the thermostat for?

That is a vacuum switch for the EGR valve. It prevents EGR operation when the engine is cold. (When connected, of course.)

Ether · #15 05-08-2012, 11:52 AM

Quote:

Originally Posted by tangofox007

That is a vacuum switch for the EGR valve. It prevents EGR operation when the engine is cold. (When connected, of course.)

I understand the EGR vac switch function. I was referring to the 1st photo in the lower left where you can see another temp switch on the other side of the thermostat.