Wiper delay mods for W124's?
 

Hi guys, saw other forums out and about but no one answers since the discussions are super old.

I heard that you can use a Volkswagen Relay (called 99 relay) to set a programmable delay for the wipers rather than the 6 second one that comes from the factory. I live in Oregon, so the mist and spit can be random. I know there is a N10 relay by the fuse box that controls the rear defogger, hazards, and wipers. They were talking about using a 99 relay that you can set the amount of delay but switching the wiper stalk to position 1, and then off really fast, then waiting whatever seconds you want, and setting stalk back to position 1 and it'll repeat that delay.


I have some of these so-called 99 relays but not sure how to hook them up as the N10 relays are pins, and the 99 relays are spades.


Anybody have any ideas? How would this 99 relay go between the N10 and the car? How does this work if the N10 pins plug into the car directly?

I had the Audi relay on my Volvo and it was the bees knees but I think the Mercedes relay is completely different. Hopefully there’s been some advances since then because I want more choice in wiper action too

I had modified a few w124 relays to incorporate the vw99 relay. Basically you remove the Mercedes relay from the printed circuit board and graft in the vw circuit board. Careful the vw relay comes in 2 forms the adjustable and the non adjustable relay. The relay with an arrow is the adjustable 99 relay. It's been years since I had done this

I saw a pic of someone else that had done this and they had removed a bunch of resistors as well as the relay off of that N10 card. I can't get a hold of them. Do you know if removing those resistors was necessary?

Instead of grafting the 99 relay's card into it, can wires from that board be run over to the 99 relay's spade connectors instead?

Resistors are not needed but 2 traces need to be cut. I can try to find my notes and pics. Yes you could mount it remotely like you suggested.

This should help.

I just now saw your pics, I just started a new job so have been busy. Now I want to revisit this. I saw your pictures, and was going to do wires going from the N10 to the VW relay (99 relay) externally. What traces do you refer to that needed to be cut?

I can't seem to recall but after the relay had been removed it should become obvious only the 99 can power something. I'll see if I can find more info.

That would be AWESOME. I live in Oregon, so variable speeds would be amazing. If you had pics of the back of the board too and exactly what wires and components went where, it'd be so appreciated!!!

Start with your 99 and solder on the wires as shown in fig 4.
Doesn't matter what colors then write the colors on fig 1.
Remove the relay from the combination board.

I may have a few I already made up I'll check hopefully later today. It's a very nice feature. Not all 99 relays have this feature look for a symbol with an arrow through it and that's the right relay.

If you could see if you have any that would be great. I will pay you.
Otherwise as long as I know exactly how to do it I can go and get other parts and have a shop solder them or do it myself because I have three of these cars. I love my 92 300D!

I have 1 assembled but not tested yet. May take a few days to get to testing it.

That is totally fine.

Looking forward to it!!! We can document in super detail how it's done so we can help anybody else that want to do this.
I can apply it to my other two cars as well.

If I had a 99 relay I would build one with you, I'll see when I can get to the Wreckers next. The actual build time is around 2 hours.

I got one I can send you...