1988 244 dl wipers quit. how do I check relay

 

Check the fuse first. I am sure there is a way to jump it, but i don't know the appropriate terminals. I am sure someone will pop on here. Preliminary check would be to find and hear if it clicks at all.

 

the relay is under the carpet on the drivers side kick panel. It is a black relay. This relay really only controls the speeds of the wiper motor particulary intermittent. Sounds like you have a bad motor. It is located under the hood passenger side top of firewall you cant miss it. unplug the connection and put a test light in the electrical connector. Make sure you have car on and move windshield wiper lever to an on position. If the test light is lit up then your windshield wiper motor is bad. If it is not lit up check your fuses...hope this helps

 

Well the wiper motor doesn't get it's power from a relay,it comes from fuse #2.The relay under the drivers side carpet controls the intermittent portion of the wipers.The relay can be unplugged and the wipers will still function on high and low.

1. check fuse #2

2. Unplug the connector from the wiper motor,turn the key to the on position,check the yellow wire with a test light or volt/ohm meter,there should be 12v present.

3.Turn the key switch to the on position,put the wiper switch to the low position,check the brown wire in the connector at the wiper motor,there should be 12v present.If you do not have 12v your switch is bad.

4. If 1-3 checks ok,you need to check the ground on the wiper motor.About 5 or 6 inches from the wiper motor is a braided ground wire going to the valve cover.Scrape a clean spot on the wiper motor,take a short length of wire, touch it to the motor and the other end to the ground wire,the wiper motor should run.(make sure key is on and wiper switch turned to low position) If the wiper motor doesn't run,the motor is bad.

5. If the wiper motor runs with the ground wire attached,the ground at the motor is losing connection.
Remove the motor,under the top bolt there will be a ground strap,(see pic)
clean the strap and also around the bolt hole with emery cloth or a piece of sand paper.Reinstall the motor and turn on the wiper switch,you should now have working wipers.



Dan

 

Would all of this apply for 78 242? MY #1 fuse keeps blowing, not #2. The fuse blows when I turn the key to "on" no matter what position the wiper control is in. I recently replaced the heater core ( the quick way, not the long way, so i did'nt have the entire dash torn apart or anything) BUt it was my first foray under the dash, So im not 100% familiar with the wiring ect yet.

Thanks!

 

Yeah, nevermind. I figured it out. The stock radio power wires were reversed. Someone cut the harness plug at some point, so its just spades going into the harness side plug. Go figure-

 

I'm new to this forums page and figured it would be wise to join since I love my 1989 240 wagon and it continually gives me headaches now and then. My current dilemma would be the wipers which quit working a few days ago.

Voltage checks at the wiper motor electrical clip are quite puzzling. I'm not getting 0 volts or what I should be reading, 12.5 volts. They are anywhere between 4-5.5 volts on both the Yellow and brown wires. This leads me to believe I've got a serious problem.

Any advice on what to do/check next?

 

you're measuring these voltages relative to ground ? (eg, yellow to ground, brown to ground, and not yellow to brown) ?

at the motor connector, yellow is switched power (on with ignition in I or II) via fuse 2. if yellow to chassis ground isn't 12 volts when the key is on, then I'd check the voltage at the fuse. if the voltage on both sides of the fuse is OK, then its the wire in between, which my diagram shows has no connectors in the middle (that doesn't mean much however).

I *highly* recommend shotgun replacing ALL the fuses in an older volvo every 10 years or so. go to ebay and find someone selling "W124 Mercedes fuses", all copper/brass, they are MUCH better than the cheap tin ones sold in Buss Fuse bubble packs at your local car parts place. Sample [url=http://www.ebay.com/itm/MERCEDES-fuse-kit-W124-W201-190E-2-3-2-6-16V-190D-300E-260E-300D-300CE-300TE-/290827844104?pt=Motors_Car_Truck_Parts_Accessories &hash=item43b6b0ba08&vxp=mtr]auction[/img]

also use a pink pencil eraser to clean the fuse holder contacts

the brown wire to the motor also comes from fuse 2, via the wiper switch, and is powered when the wipers are on normal speed. the green wire is powered on high speed, and the white/black wire is powered intermittently when the wipers are on intermittent mode, via the intermitten wiper relay.

 

Thanks for the advice Pierce. Yes, my checks were relative to ground.
It won't be until tomorrow that I can get back to tackling this problem but here's some other notes that go with my current dilemma.
This all started out of the blue AFTER I found that my rear brake lights were not working. After all the trial and error and testing with my voltmeter, I located the problem: All of the wiring had worn apart where the rear harness went through the tailgate hinge of my wagon(super poor design). During this process I did clean the fuse box contacts and replace the fuses(not with Mercedes fuses)
I was able to fix my brake lights and then a few days later when rain appeared that's when I discovered this new problem. When I purchased this car I found out from the mechanic who worked on it that it had sat for 3 years. The car was a 'little old lady car' whom quit driving it at 97,000 miles. He did say due to the sitting here in the northeast that some wiring had to be reworked due to rodent damage. The darn car is clean and mechanically tight but these electrical problems are giving me fits.
Again, thanks for the advice, I'll keep you posted.

 

afaik, the wiper motor wiring on a 240 is pretty direct, goes through the firewall somewhere near the steering column, and straight to the wiper stalk switch and fuse panel.

the greenbook is remarkably vague on where the wiper intermittent relay is. VADIS (parts catalog) suggests its under the driver side dashboard, and on a wagon, you have TWO intermittent relays, one for the rear wiper, one for the front.

 

Just wanted to thank you Pierce for the quick advice. My problem lies in the fuse panel itself. I was out there testing things today and was receiving those low readings again on both sides of the #2 fuse. I remembered when reading the diagram that #5 was an empty/spare slot. Great results once I switched everything over to #5. I'll be looking for a new fuse panel in the very near future......

 

for what its worth, the wire from the ignition switch to the #2 fuse also powers the #1 and 3 fuse, via a internal connection in the fuse block. it comes in from the ignition switch on a heavy gauge yellow wire. the hot side of fuse 1 has a yellow-black wire that's power to the headlight switch and drives the high beam relay (by hot side, I mean the side that's connected to power, so it's hot even if the fuse is out).

fuse 1 itself appears to be 'cigar lighter' and tailgate washer/wiper (on wagons). electric mirrors too, if you have them. and the factory radio.

fuse 2 provides power for the horn in addition to the wiper circuit.

fuse 3 is the heater/ventilation fan.

 

I see what you mean Pierce, as my radio, rear wiper and heater are not working now. I've got a temporary jumper for the heater because I'm in SW Pennsylvania and it's a bit cold right now. I'm having a hard time locating a new fuse panel though, thought I would ask you if you have any suggestions where I should look.

David

 

the fuse panel is pretty darn simple. clean the contacts with a pink pencil eraser til they are shiny gold, and use new fuses, preferably the brass/copper european ones (the typical silver/tin ones sold in the US parts stores are awful)

if the voltage is good on that yellow wire from the ignition switch, and the spade that connector goes onto is clean, its really hard to understand how you'd see low voltage on the 'input' side of the fuses 1-3, as the input contact and the fuse clip are the same piece of metal. unless its corroded, whereupon see: 'pink eraser'

best place to get the GOOD fuses for these cars is from ebay, search for 'Mercedes W124 fuses" (W124 is the code name for a late 80s, early 90s 300D/300E kind of car), and there's various folks selling enough fuses for the whole car with plenty left over for cheap. these european fuses are all copper and/or brass rather than aluminum and tin, they will last MUCH longer.

 

Ive been following the thread because of my problem on 89 Volvo 245GL with wipers quit the day after a heavy rain storm. Had been having problems off and on with quitting and returning to operate though only one speed and very slow. I tested for power at the connector and it tested 12v so I purchased a remanufactured motor and still the same problems. I'm stumped! I've cleaned the ground and ran a test wire from ground strap to motor to the wiper motor and still nothing. I've tested power at the fuse box and I have 12 volts but only on one side of fuse 2. Maybe I'm doing something wrong. Any suggestions?

 

if you only have power on one side of the fuse, its a bad fuse. btw, the three spadelug terminals next to each fuse, the one closest to the fuse is connected to the right fuse clip, and is the 'input', while the middle and farthest away spade are connected together and to the left fuse clip, and are the outputs.

I *highly* recommend replacing ALL the fuses in a 240 with the copper/brass ones you can find on ebay sold as 'mercedes w123 w124 fuses'... clean the inside of the fuse spring-clips with a soft clean pink pencil eraser while you're at it. one of those mercedes fuse sets is enough for 2-3 240's.

 

Thanks Pierce...replaced the fuse and I have power on both sides of the fuse. I used a test light to check ground and also for the connector and I have power at yellow, brown, and green wires. Still nothing gets the motor to come on. It doesn't even make a sound and it's rebuilt, the same as the previous motor. I'm getting the impression I have gotten a defective motor. Any other suggestions would be greatly appreciated.

 

FWIW, the yellow wire is always powered if the ignition is on, thats used to return the wiper to home. the green wire is powered for high speed mode. the brown wire is powered for normal wiper operation, and the white-black wire is used for the intermittent mode to tell the timer relay that the wiper isn't 'home'.


and yeah, if powering brown doesn't run the motor (with the ground wire connected to negative), then its a dead motor.

 

Thanks Pierce...bad ground, new wiper motor is good.

 

Now that motor installed and operating one problem remainds. The wipers only work when arms are off the windshield. Soon as wipers are on windshield the arm stops and motor continues to run. I suspect this may have caused first motor to quit. While observing the linkage operate I see nothing binding; operates smoothly without any cluncking noise but will stop as soon as I put the wipers back against the windshield. I've also observed that the driver side wiper on the windshield will work without jamming. Would a cable out of adjustment be the cause?