DIY restomod wiper function

[Forssling]

Hi All,
let me start with that I'm not an electric engineer or anything close to that. So if you do this mod it's on you. All I can say is that it works for me...

So I have a -71 911T that I'm restoring. I bought it as a project in boxes. Working the wiring I soon found out I have the notorious, one year only, SL35, wiring. That includes the two relay setup for interval wipers.

I didn't get this working and having two speeds only with a notch on the switch not working was just not for me... So I started to investigate how to make a new setup with, interval, slow and fast, just as it's supposed to be. This is the short version. Feel free to ask questions and I'll answer them to my ability.

You need:
A few connectors, male and female
2 diodes that can handle 5A
A interval timer module
(I bought Velleman VM136)
A box for timer module
Some wires
Shrink wrap tube

Make two wires with the diodes. A male connector on the "stop" end and a female on the "in" end on one of them. Leave the other one without. I had some shrink wrap on them.





Make a wire with a male connector in one end that splits to three female connectors. Note different lengths and where diodes go and the arrow showing direction of current. If you have black/purple wire, this is the time to use it.

Make three wires approx 8" long with a male connector in one end. If you can, make them, blue, red and brown.





Now you have four open ends of wire. Connect them to the timer module:

Blue wire - 12+
Brown wire - GND
Red wire - NO
Black/Purple - COM



Connect male connectors to:
Blue - to blue 53a on relay socket
Red - to red 53a on the other relay socket
Brown - to brown 31 on any of the relay sockets



Connect to wiper motor:
Black/Purple with diode - to 31b
Black/Purple - to 53

The other connector on the wiper motor is the original:
Red/White - to 53a
Black/Yellow - to 53b
Brown - to 31 (ground)





Thats it. You set the pulse and pause on the timer module. So if you want it to to make two runs with the wipers set it so it gets current to start the second swipe. The park mode takes over when it's outside park. Set the pause for how long you want to pause.

I'll post some schematics in the next post.

Jörgen Forssling
Gothenburg
SWEDEN

[Forssling]

Here are some schematics as promised. Mind that I'm not professional doing this, but I hope they help you.

//Jörgen

[ian c2]

Great little project .
For those that want a simpler solution that has variable timing using your existing stalk , look at smart-screen etc.
It will cost about double what it costs to make your version .