Where is the plug for my Heater Pump? 300SD - PeachParts Mercedes-Benz Forum

LNGfish · #1 02-23-2009, 11:40 AM

I have found the pump but it is real hard to see the wires connected to it to trace it back to any plug. I did find a connection plug that is located between the battery and the monovalve. It hangs in a metal "sling bracket" with Barbs. It is Rectangle shaped with a brown and a black wire to and from.
The plug is dark brown or black.

I want to disconnect it for now and install a 1A fuse in it once I get the fuse holder and fuse.

I don't want a fire.

Is this the plug?

Thanks in advance.

Steve

bgkast · #2 02-23-2009, 11:58 AM

That's it. The plug is very close to the motor, and does hang on a clip on bracket.

Graplr · #3 02-23-2009, 12:01 PM

By Heater Pump, I assume you are talking about the Auxilliary Water Pump.

On my 84 SD, the wires from the aux pump have a black plug on it. The plug rests on a bracket right next to the monovalve where it plugs into another black plug. I don't believe there is anything else in the area the the plug will fit.

You should be able to follow the wire from the bracket to the pump itself.

bgkast · #4 02-23-2009, 12:07 PM

BTW DeliveryValve Makes a nice fuse that just plugs in to the pump plug. I use one on my car.

http://www.peachparts.com/shopforum/showthread.php?t=242553&highlight=fuse

LNGfish · #5 02-23-2009, 12:30 PM

Thanks for link to Delivery Valve. Yes his set up looks good. He is sold out however.

I'll PM and see if he still makes them up.

Where he shows it in car installed, is that the pump itself? Wow, if it is, I can hardly see mine at all will all the hoses laid on top on the SD 126. I think his car is a 123 so maybe easier to see and take a picture. I'll look closer but I'm not taking any hoses out to get to it, lol. I hate not being able to trace it back. Used flashlite and all.

Who designed these cars, Germans?

bgkast · #6 02-23-2009, 12:32 PM

Yes, that picture is a W123. The pump is hard to see down there between the two firewalls on the W126.

tyl604 · #7 02-23-2009, 01:00 PM

Can anyone post a picture? I would like to see if my '81 300SD has an aux water pump.

LNGfish · #8 02-23-2009, 01:11 PM

I pulled the battery out and traced the wires from Plug to Pump. You can see bettery with battery out on the 126 for sure but stilll not 100% view, but the Brown and Black wires head straight towards the pump and the plug was between the battery and the Mono Valve as I had suspected. Very easy to see the plug to the last fellow who posted. Black/Red positive and Brown Negative.

I needed to clean out under the battery anyway since the mice vacated, and paint the tray and clean out the leaves. Fuse goes in Black/Red wire.

I'll get the Napa 7823101 Fuse Holder and the Napa 7821042 1 amp fuse. I think I'll get the Napa NW785117 post disconnect if they stock them.

I'll be happy to get the 1 amp fuse installed in this line.

LNGfish · #9 02-23-2009, 01:15 PM

TYL604

I'm thinking you have one on your 81 SD as mine is an 82 SD unless it was removed.

The pump is located in the tray behind the engine and in front of the firewall.

It is approximately in the center about 10-12 inches down. It is connected to hoses.

It's diameter is about 2 inches. Pump on end of motor shaft all on one plane, like in series.

If it's there you will see it just look carefully the Germans hid it.

Graplr · #10 02-23-2009, 01:20 PM

Quote:

Originally Posted by LNGfish

I pulled the battery out and traced the wires from Plug to Pump. You can see bettery with battery out on the 126 for sure but stilll not 100% view, but the Brown and Black wires head straight towards the pump and the plug was between the battery and the Mono Valve as I had suspected. Very easy to see the plug to the last fellow who posted. Black/Red positive and Brown Negative.

I needed to clean out under the battery anyway since the mice vacated, and paint the tray and clean out the leaves. Fuse goes in Black/Red wire.

I'll get the Napa 7823101 Fuse Holder and the Napa 7821042 1 amp fuse. I think I'll get the Napa NW785117 post disconnect if they stock them.

I'll be happy to get the 1 amp fuse installed in this line.

You can remove a section of the front firewall for easier access. The panel that removes is basically the section directly behind the engine. There are 4 bolts, 8mm I believe, maybe 10mm- 2 on each side, 1 up and 1 down. Take those 4 bolts out, pull up the rubber on the top and slide the firewall out. It makes for easier workspace for anything you are doing back there.

LNGfish · #11 02-23-2009, 01:21 PM

I'm not sure how to post pics yet or I would. You'll find it just imagine you were a German and your were trying to hide something to cause a fire later on.

LNGfish · #12 02-23-2009, 01:26 PM

Graplr, OK Thanks! for the mention of an access plate! I'll scope it out. Maybe this is helpful the the other fellow. It was good to get battery tray out.

Some of the leafs have 1982 stamped on them.