Author Topic: Wiper motor problems (Read 4841 times)

nanotech9 · « **on:** June 26, 2011, 09:03:22 PM »

I've owned my '91 318is for about 10 years now... this is my second wiper motor replacement... last time was about 5 years ago, the "new" used JY motor went out about a year later... about the same time the car stopped being a daily driver...

fast forward to now... still not a daily driver but trying to get it somewhat reliable again. Motor has been non-working, or sometimes partially working on HIGH for years now... mostly non-working these days. A while back the washer started running full-time no matter what... so the washer pump connection got pulled to keep it from burning up.

I picked up ANOTHER used wiper motor locally from a guy parting his car out. Says it worked good. I just pulled the old motor and decided to hook up the "new" motor before i reinstalled it...

Funny thing is the "New" motor only works on HIGH as well. I'm suspicious of another problem.

I whip out the Fluke 89 and a copy of the wiring diagram, and test the wiring harness side plug... across BRN (ground) and BK/WT i get 12v on the HIGH setting, which is correct. Between BRN and BK/YL, (should be the slow side) i get no voltage with the stalk set to slow, or intermittent.

I also checked the voltage on the pump motor and noticed its functioning properly with the stalk squirt position, so i plugged it back in.

So, now i'm down to either a bad stalk, or a bad washer/wiper relay.

I pulled the long black relay (biggest/only one in the fusebox) and gently opened it up... everything *looks* ok... i use some 600 grit sand paper to gently clean both sides of the contact points on both internal relays and the legs as well. Re-inserted with the cover off... as far as i can tell only ONE of the relays is working... when i switch the stalk to HIGH... however its difficult to turn it on and watch the relays at the same time.

The only thing i have left to try is to figure out the stalk wiring and check voltage at it, and of course try another relay.

Does anyone have any suggestions?

Also, how does the motor know where to stop in its rotation every time, and should it stop in that location even when not installed in place? I would assume its the break in the internal ring, and YES it should stop in the same spot while not installed, but not sure.

*** Note, i DID make sure the rings and contacts inside the wiper motor were in good condition, brushed the contact points with 600 grit paper, lightly, and reassembled.

DesktopDave · « **Reply #1 on:** June 27, 2011, 07:02:12 AM »

I'd say bad stalk but I don't have the test method handy. Those wiper motors usually last a long time, might be a short in the harness to the wiper motor. Good thing too, replacing the wiper motor is one of the ugliest jobs on an e30.

nanotech9 · « **Reply #2 on:** June 27, 2011, 09:17:44 AM »

oh, come on now... its not THAT bad... Although i'll admit the first time i did it w/o any instructions years ago it was HORRIBLE!... This time around it wasn't bad at all... I even had to remove my home-made strut tower brace, and disconnected half the wiring...

looks like i need to start ripping apart the steering column...

DesktopDave · « **Reply #3 on:** June 27, 2011, 05:12:39 PM »

The stalk is easy (but you knew that). Pull the wheel, unscrew the lower steering column case & you can easily get at the stalk fasteners. Great time to install cruise, BTW.

nanotech9 · « **Reply #4 on:** June 28, 2011, 10:34:06 PM »

the good part is, years ago i fitted another wheel (3-spoke) off another BMW and had to make some spacers... which leaves me room to take the bolts out of the column plastic w/o removing the wheel (barely!).

bad news is i installed the "new" stalk and relay, and theres NO change.

time to go stare at the wiring diagram a little more and see where the problem might be.

For sure ground is working because it completes the "High speed" circuit. That just leaves the hots. If i weren't so lazy i would have checked that first....

The car has been over at the brothers house who kindly stored it (instead of his newer nicer cars) in his garage... of course for some time my sister-n-law drove it when her car was T-boned (with 3 kids in it!) in a hit and run... During this time they claimed to experience a BURNING smell from the dash (oh noes!) and thought it was the radio, so they turned off the radio. This was around the same time the washer pump started running nonstop....

When i picked the car up last weekend, i punched the code in the radio (from memory after 2 years!) and the antenna popped up as usual, and the radio has worked fine ever since.... I'm thinking the burning smell might be related to the wiper circuit now. Hummmm.

I hate tracing electrical problems.

DesktopDave · « **Reply #5 on:** June 29, 2011, 09:37:19 AM »

While pulling the entire wiring harness from the dash is a good day's work, I'd definitely consider attacking it that way. You can still drive the car if you need to, and if it'll prevent the car from burning I'm all for it. You don't need an M42 donor either, every later model e30 is more or less the same.

nanotech9 · « **Reply #6 on:** June 29, 2011, 11:23:52 AM »

Man theres easier ways to skin a cat...

I'll just re-run a new loom just for the wipers and completely bypass the old loom if i have to before i yank the entire wiring harness! This old car is a long way from being stock or purist anymore, and swapping a wiring harness sounds like work! I'm allergic to work! lol.

Back in the day when i did my window switch conversion (i think i was one of the first - nobody had any info on doing it at the time and nobody i knew on the forums had ever done it) i took the time to bust apart an old set of stock switches to use a plugs to splice into a short part of an e36 wiring harness to make a conversion pigtail so i didn't have to cut my car's wiring harness... fast forward 10 years... one pigtail broke (i think). Pretty sure the e36 harness is just gonna get spliced straight into the e30 harness this time

Snip Snip.

nanotech9 · « **Reply #7 on:** June 30, 2011, 12:30:43 AM »

well... more good news.

I started out checking the grounds from the schematic... those looked good.
I checked to make sure my switch worked correctly - it did.
Then i started tracing continuity from the switch to the fuse box (the switch basically passes ground on several different wires to the big relay in the fusebox).

Easy way to do this was the schematic has the relay pin labeled on it, and of course they're labeled on the bottom of the relay as well... translate that to the pinout on the fusebox and it all makes sense...

High speed checked out OK of course, and then i went to test the low speed, and looked at the hole in the fusebox and realized there was no metal on the "inside"... oops. Turns out the connector on the backside had pushed out of the plastic slot and wasn't making good connection.

I opened up the fusebox (three screws, top left, bottom, and bottom right under the foglight relay) and shoved everything back in place while re-installing the original wiper relay.

Everything works now... well, aside from the washer PUMP which i've determined is burnt out, and probably what my brother/sister-n-law was smelling inside the cab. Still smells burnt even now.

So, there you have it... check your wiring/connections - pretty easy for it to be one of the causes of only half of the windshield wiper speeds working. (although i also believe my original replacement motor was burnt/burning out as well - it was very weak on high and sometimes didn't work at all on high).

So, i'm off to find a washer pump motor

DesktopDave · « **Reply #8 on:** June 30, 2011, 07:16:25 AM »

Mine is dead too. $22 at Pelican. The earlier model (I have a spare) doesn't fit, what's up with that?