Any update getting this to work on a W124?

I installed it in one of my W124's. Instead of messing with the wiring in the base of the multifunction relay, I modified a couple of spare N10's to have pigtails coming out of the module going to the 99 relay. This allows me to switch back to the original N10 without much work if needed. The first N10 got in-line connectors to relay 99 but the second went directly to the VW socket. I figured if I wanted to remove it I could just remove the terminals from the VW socket (the VW socket was too large to go through any of the open holes in the relay center). There was no room in the top portion of the relay center so I mounted 99 below fastened with a nylon tie.

Relay 99 has been working great. The other car will have to wait until I pick up another VW relay.

Photos show 2 different versions of the 201 821 00 47 made by different manufacturers. Components connected to the wiper related pins have been removed.

Edit: I need to update the second photo. There is one diode that is removed that needs to stay installed (from terminal 15R)

Nice mod! I had thought about trying that too.

Hmm, one of the relays in there must be for the wiper motor. I wonder if it could be removed, and the guts of the VW relay put inside the MB relay case....

-J

The wiper relay has been removed already. The remaining 2 are for signal flasher and rear window defogger. I would have liked to put the VW guts inside but I can't see there being enough room.

Edit: I opened up the VW relay again and it might just fit in N10, especially the first one pictured that is mostly surface mount circuitry on the bottom side of the board. A project for a cold winter day.

VW relay 99 circuit board added inside N10 multifunction relay.

This is in a relay manufactured by a company with a symbol that looks like JWT that is almost all surface mount. A few components had to be removed, a trace cut and a couple of components relocated to get the 99 inards to fit. The board gets held in place by non-corrosive RTV.

The other common manufacturer which has the symbol LK in a circle would be much more of a challenge as the ones that I've seen are through hole technology with little room.

Nice work! Your W124 solution gives a completely factory appearance.

I'm glad you mentioned non corrosive RTV because it's critical for electronics. Acetic acid from conventional RTV will eventually destroy the board.

When servicing boards many times you'll find a large cap will be glued to another component using glue or RTV. When replacing these parts the adhesive used must be safe for electronics.

Oftentimes the replacement capacitor will be much smaller than the original negating the need for adhesive support. However, large parts will need the support to avoid cracking the solder joints on the board.

Has someone gotten this mod to work on an '83 SD? I tried with two separate 99 relays. Both have no interval function and no return to park function. AFAIK the wiper relay wiring is identical between the 83-85 SD and 123 down to wire colors. On the plus side futzing with the relay socket got my washer pump working again.

I'm quite sure it's a poor connection somewhere :/

Sixto
83 300SD
98 E320 wagon

Very, very cool! Thanks for posting.

Unfortunately none of the N10s or 99s that I have are the versions required to make this work as you have. I will probably solder the wires on the yellow board N10 as you did in the previous post directly to the blades on the 99. If I affix the 99 to the right side of the N10 there's looks enough room in the W201 fusebox area for it to fit by the two aluminum-housed ice cubes, but definitely not both the relay and socket.

I'll keep on the hunt for the N10 and 99 that you're using. The correct 99 may take a while to find, but I should at least have the variable int wipers running soon.

There used to be a forum member who made an infinitely variable wiper relay. His name was techguy512, but I don't think he is around anymore. I bought one and love it. I should have bought two...

The 99 relay that I used had only 2 components on the top side of the board, a relay and a 1uF 50 volt electroytic capacitor. The relay gets removed and I added a surface mount capacitor on the copper side to replace the 1uF. I used the SM cap only because I had a bunch that I'll never use up. A conventional cap could be mounted horizontally. I ground the circuit board down on the connector end to make it as small as possible. Looking at the photos on page 2, I would imagine other versions of the 99 could be made to fit.

When I get another 99 relay I'm going to mount one in the LF N10 module.
There are a few capacitors that I'll replace with stubby ones to get enough room. I just don't like gluing the 99 circuit board to the component side of the board but it has to be securely mounted.

A long time ago, I made a circuit for my first car, a 69 Sunbeam Alpine.
It had 2 adjustments. An interval setting and another for the number of wipes per interval. It wasn't my design but one I found in an electronics circuit book.
It was luxury to have that feature back then.

Were the SD and the 99 relay fully functional before you did the mod?
I have installed a 99 relay in my 92 VW and used it a few times in the rain and love it so much that I'll be converting my 85 300D to a 99.

I have 3 more 99's coming from Europe. They will be tested in my VW before the conversion of my W123. I'll have one extra (or two, depending if my 81 VW Caddy will accept a 99) tested 99 relays available. pm me if interested.

The original relay was working except for the washer feature which came back to life after refitting the relay. I have two 99 relays from the scrap yard but no way to test them. At this point I don't even know that the relay wires I added from a tail light harness are making contact with the fuse box socket. I'll obtain another MB relay so I can be sure the wires are making contact.

Sixto
83 300SD
98 E320 wagon

The movie about the invention and lawsuit of ford over the "blinking wiper motor" is on Netflix... cool movie.

Flash of genius

Ford crushed the poor guy, didn't he?

I'm able to hear the intermittent motor and relay going if I listen for it in my 123.