Sleepwalker,

Thanks for your help on the instrument cluster pin connector. It was just the right thing. I will have to wire it up tomorrow.

Please see the post on:

https://mercedesforum.com/m_43896/tm.htm

I never resolved this problem. I need someone's help. Please see my VIN number below. THe air compressor is not working, the blower blows hot air, and the auxiallary fan is not working. The relay on the firewall you showed me does not exist at that location in the above post for my model (3/85).

It is getting very hot in Texas now, and I need the car and the air. I am afraid that if I take it to a mechanic, it will cost a fortune to locate through electrical problems. Your drawing on the instrument cluster was perfect!

Can you please work with me the next few days to try and pin down the air problem? I do have a volt meter, but as you know, some of these plugs have many poles on them.

Funny enough, the moon roof has also quit working. I notice the red coil wire is very hot when the ignition is turned on. I do not have to start it for the red coil wire to warm up.

I have tried used relays from the salvage for the fuse box, and for the following parts under the passenger dash:

Bosch - Temperatureregler - 000 822 0903 1 147 328 023 12V
Bosch - Geblaseregler 12V - 000 822 1103 1147 328 026

 

was it really HOT air or just WARM air?

 

your car got the old version a/c system.

the switching unit is located beside the blower. check it out for corrosion or loose contacts.

there is a temperature switch on the evaporator. check it out if it's working.

make a jumper on the pressure switch and see if the compressor clutch engages. tell me the result. (engine and a/c must be running).

the pressure switch is attached on the filter/drier. if you see two switches (the other is temp), choose the lower one.

one of the flat plug should have voltage. if none, check the fuse.

 

depends on the temparature outside. If it is cool outside, it blows cool but not cold air.

 

it was the pressure switch on the drier. I could have sworn I jumped that one before, but aux fan works good and so does the compressor. I did replace a relay in the fuse box. Maybe that had something to do with it. The coil wire does not seem to be too hot anymore.

Now, if I can figure out why the moon roof quit working. I am going to wire up the instruments now.

Thanks for your help!

 

you're welcome.

 

Sleepwalker,

Something else is wrong. I drove the car last night to put in gas. The air conditioning worked fine.

Today, I drove across town to work, and went over to my friend's house (he has the equipment to draw out the freon and replace it), and the compressor and aux fan quit working again. I drove with the jumper on (where the pressure swithch was).

Also, the red coil wire is getting hot again, and the contact on the #11 fuse was hot (enough to turn it blue). We changed the fuse, and tried the relay for the compressor in the fuse box. Still, no aux fan or compressor.

What to do next? He checked the charge again, and it is full of freon.