My 1994 Benz, E320 does not run on first speed when outside temperature is close to freezing as well rear defoger heater goes out at the same time. They work fine all other times. Can you recommend the fix or direct where the problem may be and if a journeyman can tackle to repair himself?

Are the windshield wipers on "on" or on "intermittent" or "automatic"?

It could be the sensor if they are on automatic.

Same with the rear defogger - automatic or do you turn it on and off?

On the defogger, clean the connections going to the rear window element with #240 abrasive cloth and apply dielectric grease. Also, check the defogger fuse, which is usually located in the under hood fuse box with a test light or multimeter, after turning the ignition switch to ON. Remove the fuse, clean with abrasive cloth, and apply dielectric grease.

For the wiper problem, check the multi-function switch. Carefully, try taking it apart and cleaning it. Try spraying the switch first with WD-40. I would also check the fuse going to the wipers with a test light or multimeter. Remove fuse, clean, and apply dielectric grease. If problem persists, replace switch.

Personally, I would test all under hood and under dash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-t...tml#post252145

Be very thorough, since it can save a lot of time and money.

How do take apart the multi-function switch to check or clean the contacts?

The wiper works on medium and high speed but goes out in low speed only when the temperature is near freezing and works fine in warmer temperatures. At the same time defogger goes out but comes back when temperature is warm...