My climate control on my 1983 300sd has a few problems. It doesn't matter what button is pushed, it stays on windshield. I replaced the ccu with a rebuilt one and it hasn't changed. It also blows fuses. I cleaned the fuse box and replaced the fuses and no change. The weird problem is that when it is turned on, the windshield wipers cycle on a couple of times. Any ideas??? Thanks

Sounds like a bad ground


ground points:


https://www.startekinfo.com/StarTek/outside/12253/program/Chassis/54-100.pdf


climate control wiring diagram:


https://www.startekinfo.com/StarTek/outside/12253/program/ETM/ACC83-85.pdf

Thanks. I will check all that out

I found out the overheating fuse problem was the auxiliary pump. It was seized. Still haven't figured out the other issues

Glad to hear...what issues are remaining?

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

The wipers come on when I turn the climate control on and it doesn't matter what switch I push, it stays on windshield

I replaced the ccu and no change

The wipers...the ground info from Christuna will likely be a huge help to locate and clean the ground connections. That is what I'd do next; but, there is a fair chance the new CCU has been damaged from the current overload and defaults to windshield clearing.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Thanks

Before you mentioned this, I was going to suggest checking the aux pump. I've seen these seize causing the climate control to go into default which is defrost only. Did you unplug the pump.

I did. I just checked to see if the climate control worked and it is still only on windshield

The wiper is solved, I think. I unplugged the switch on the column and found a loose wire. I fixed it and now it doesn't do it now

I mean the wipers don't come on by themselves

Could the blower resistor cause the unit to default to windshield,also? I just noticed the low speed isn't working.

I don't think the blower resistor would cause this as all individual elements of it would have to fail. IIRC, the resistor is on the RF fender well in a metal cage. Check each coil for continuity and resistance.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer