Hello all. This is for people wondering about the relay replacement as documented at http://www.zapta.com/tal/rx7/wiper/main.html

I made two attempts at this, the first time really messing up the circuit board, so I thought I'd share my mistakes so someone else doesn't go through what I did!

1st attempt: I used a 40-watt iron, had a desoldering bulb, and standard 60/40 solder. The iron was too hot, and I ended up lifting stuff off of the board. The solder was extremely difficult to remove, and so as a result the relay was as well. Really didn't look like there were connections where there should be. When I put the switch back in the car, it didn't fix anything. (Only worked in lo speed.)

Feeling desperate and starting to look around for a switch for sale, I consulted my cousin and took a 2nd stab at it.

2nd attempt: I got a 15-watt grounded soldering iron, a desoldering braid (wick), some thin wire, and lead free solder (this solder was thinner and was told that a higher tin-content solder would be easier to work with). All of my materials were bought from the local Radio-Shack by the way. The desoldering braid soaked the solder right up, making relay removal much easier. The 15-watt iron also had a smaller tip which made things a little easier. I had to use the wire to make connections on the parts where stuff lifted off of the board from too much heat from my first attempt. I put the switch back in, and now the wipers work in both speeds, mist, and when I turn the washers on the wipers turn on as well. However the intermittant still doesn't work, they don't return to the "home" position correctly, and the rear wipers still don't work. (Don't have the relay part number for the relay nearest the rear wiper switch, also wonder if the relay nearest the hazard swith deal with the wipers?)

In closing, having the following will help you greatly if you decide to do this:

- A lower wattage soldering iron

- A desoldering braid/wick (a desoldering bulb is also nice as it takes of a majority of the solder but won't take off all of it)

- A hole of some sort for leverage when prying out the relay (i don't have a dremel so I hade to cut the plastic side off with a wire cutter, not a clean way of doing things!)

- Patience!!!

I think if I had a the lower watt soldering iron and a desoldering braid in the first place, I would have replaced the relay without any problems.

 

Thank you. I'm thinking about it. Have been for about three years. Been through about three from the wreck yard. Not a one lasted a week. I've done the ECU transistor repair which was easy because of the space available to work. The wiper ...some day.

 

Yeah,I would have to agree that desoldering braid is a must.

 

So cleaning contacts doesnt do **** eh? I got the same problem, waiting to find a junkyard one to fix so I can atleast have one speed if I f^#@ up. Rain-X will help while waiting

Joe

91 TII
83 GSL

 

Actually, I just fixed my wipers a few days ago. I only had low speed, and thats it! Int wouldn't work, neither would High speed(thereore the one touch spray/clean wouldn't either)), and they wouldn't park by themselves. The rear wiper wouldn't work either.
It is JUST due to dirty contacts on the relays. There is always a little bit of arcing every time the contacts open or close, causing gradual buildup. Just clean it off REALLY WELL!! If there isn't a good connection, it isn't enough to close the circuit, and also not enough to flip the relay back to the opposite position.

Here's what I did- NO DESOLDERING.

-I just took out the wiper switch
-Using a dremel, I cut the cover off of the back of the unit
-I pulled the covers off both of the transparent Omron relays
-I pulled the contacts back and gave them a little grinding with the dremel. LOTS of buildup.....
-Plugged the switch back into the car, the adjusted the clearances between the contacts a bit, just to get everything working perfectly- EVERYTHING WORKS!!! I just put the covers back on the relays and re-assembled the dash pod.

I like having working wipers, all speeds, Int, and rear.. wow.....
Took much less than an hour......

Just be carefull of the screw mounting holes in the plastic of the dash binnacle.. They are pretty brittle... I had to use a bit of JBweld to re-create some screw holes...

I have never seen a mechanical failure of the relays, it is always just carbon buildup from arcing. They probably have to be cleaned every 6-10 years or so. (Mazda.....) Of course, if you feel like going through the headache of replacing the relays, go ahead, but due to the voltage at the contacts (not the best design), they will still have to be cleaned eventually too....
Hope I saved you guys some trouble!!!

 

I tried sanding the contacts but found that it only lasted a month. The best solution that I found is to order the exact relay from an industrial electronics store, then solder it directly in. I have done this 3 times and haven't had them apart since. The part number I order is G6C2117PFDUSSVDC12 made by Omron. It is only $7 Canadian. I use a pencil type iron on high heat with a vacuum type solder remover(radioshack part#64-2098). The last one I replaced took 45 minutes from start to testing. Gentle prying and working from one end of the board to the other insuring each pin is desoldered is the easiest way I found.

 

I did the wiper switch fix and lifted a lot of cuircuits off the board. Instead of starting over I took 6 small sections of wire and soldered them to the board (both sides) so they made contact then soldered them to the relay. There was still enough room to jam it all back into the switch and it works like new.

 

I'll take advice from both sides of this issue. I just removed the relay and I'll sand the contacts and reinstall. Then I'll order three of the relays( I know it takes only one, but what if?) to be installed whenever they get here and install one. At least I'll have some wipers to help the Rain-Ex(darn good stuff. I can drive at 70 without wipers). The solder wick did wonders on the removal, and patience is required. By the way, is'nt that carbon buildup just material being taken from one side of the contacts and being deposited on the other? Like there is a pit on one of the contacts, and a hill on the other.

 

i prolly did mine the wrong way, but in my old car i just used a simple 5 dollar iron and tapped the solder points. that seemed to melt the solder quickly then reform it again. worked fine for me. fixed my clock, etc. the solder points were visibly cracked under a mag. glass when we inspected them. they were solid afterwards..

 

I really don't think that replacing the relays are required.... The reason most people only get a little bit of life out of freshly cleaned contacts is that they aren't cleaned enough. I took a dremel to mine and made SURE they were right down to bare metal.... They have to be TOTALLY clean... just a tiny bit of carbon can lead to a poor connection, wich causes more carbon...you get the idea...

It's a tiny bit of metal being vaporized and leaving only a trace of carbon behind... just like how spark plub gap can increase over time due to losing metal....
The pit on one side is the metal lost.... the hill on the other is carbon that has just been shaped to the contour of the hole on the other contact when closed...

Using some dielectric grease (contact lube) can prevent the arcing and carbon buildup after cleaning.