Well, I already started a thread about my 190DT but this one will be strictly electrical issues.

So far, it seems as if the Klima is missing, the blower motor wire is melted/gone, and there are some other melted wires behind the dash.
The Klima is missing. The motor wire has been rerun. No longer melted wires!

The tach, clock, coolant gauge, and A/C do not work.
The tach and clock now work. Need new coolant temp sensor for coolant gauge. A/C requires Klima Relay

I just found 3 suspicious looking connectors I will post pictures of. (Sorry for the poor quality, it was getting dark outside and they were taken on my cell phone) The are all on the driver side of the engine. The two that are disconnected look to go to a group of wires toward the fender. I did not follow the connected wires, but it looks like it is a two wire connector with one wire improperly connected and another one missing.
These are for the windshield wiper fluid container I am missing

Please help me anyway you can. This looks to be a big job, and I really would like some help.
Still need the help!

Thanks in advance.

Attached Thumbnails

     

Well I ran the test and the 87L pin does not receive 12V.

Could this be the cause of my problems?

I think it is. I jumped the other protected pin to 87L and my tach is now alive!

The coolant temperature and exterior temperature do not work still. Any suggestions? The resistance from the pin on the sensor to the block is infinity. If I jump the wire to ground the gauge pegs at max temp. I am pretty sure my coolant temperature sensor is bad. Is the KAE replacement brand any good? I am going to stay away from Uro!
Still need to get the exterior temperature working!

I don't think the outside temperature gauge is getting power, and the bumper on it isn't stock so there might not be a sensor at all.

I removed my dash to do some wire hunting. The wire that goes to that single fuse holder originates at the ignition and then must go on to the blower motor. The wire was melted and corroded. It looks like there might have been two in the cluster that went to the ignition. I will work on that soon I guess. Do I need the Klima for the blower motor to work?

you need a high detail schematic for your chassis before proceeding. then you can trace the wires from your mystery connectors and identify their purpose.

i just replaced my coolant temp sensor and i can confirm that the correct resistance is less than infinity. hold the nub of the sensor in your warm hand and watch the resistance decrease.

__________________
'77 240D, 504H, OM617.952, etc.

Does the FSM have a high detail schematic?

Then my coolant sensor is definitely bad!

Well I took the wire off of the single fuse in the engine bay and tracked it back towards the ignition.

Once I got behind the steering while that wire went to the left. It's red and blue and seems fine.

Then I went towards the ignition. That's were the real melted wire was.
50 purple white
15R red green
P30 green white
15 red black
30 red
15x red yellow melted!!!!!!
30red

15X I think had two wires coming off of it. The smaller gauge red yellow and the unrecognizable wire. Do you know where it should go? I can rewire it. I just need to know an end point. It must be close to where the fuse in the hood was since I think they traveled together out of the car.
The red yellow goes to the single fuse and then to the red blue

I found the last image in the Power Distribution section of the FSM, but I still don't know where it goes.

Thanks!

i've never seen the FSM for your car, but it looks like you found at least a part of the schematic there.

__________________
'77 240D, 504H, OM617.952, etc.

also, googling that part number may help you find the part on the schematic, which would tell you what wire that is.

__________________
'77 240D, 504H, OM617.952, etc.

I think someone helped me figure it out. Though they said that shouldn't be there at all so I am confused!

Does anyone know if you need the klima relay in order for the blower motor to function?

The mystery connectors I believe go to the windshield wiper fluid reservoir that is missing

I will hopefully be replacing my coolant temp sensor on Friday.

I have the wire rewired the way it should be, I think, but no fan still.

Need some more advice!

I checked the voltage at all of the fuses while the car was running. I received the proper voltage on all but the following:
1 1.45V (connected to 15X!!!)
4, 5 5.25V (Headlights were not on)
14, 15, 16, 17 0V
18 1.25V

Some good news.

I check the continuity between 15X and fuse 1. Good to go there. So then I open up the ignition. The copper was not getting connected in the ignition. Bend it around some and I am good to go. Turn the key, the aux. fan comes on. Wires start smoking! I find the problem! The PO had the aux fan wired straight to the line and I guess those motors must be bad? I disconnected that and now I have 12V at fuse 1. Wahoo!! The blower motor works now! Wahoo!

But the headlights don't work this has happened before and I just left it over night and it worked again in the morning. I know I have my work cut out for me, but I AM getting through it piece by piece.

Thanks again!