'85 coupe.

Non-functioning wipers in any speed. Here's what I've done so far:

I can see an amp draw (gauge drops) when I turn the wipers on, so I
pulled the motor (removing the duct-tape-and-soda-bottle rain
shield) and disassembled it. The linkage independent of the motor
moves freely so no issues there. Open it up and it's clean and
very greasy, and the gear is in excellent shape. No issues there.
I then took the motor to my local electric guy for a checkout. He
gave it back to me telling me there was nothing wrong, some powdery
rust inside but he cleaned up the brushes and commutator and it
should be fine. He actually didn't charge me for it.

I should note neither he nor I could figure out, either with the
help of the ROM or Kirby's book, how to get the frigging thing to
run on the bench. This ridiculously overcomplicated setup has us
stumped as to where to apply power and ground on the bench to get
the damn thing to run.

Got home and plugged it in and it still didn't run. On the plug
attached to the cowl (fat 8-pin one) I do have a pin with good
continuity to ground, one with 12v in high, one with 12v in low,
and another big one that has 12v both in off and delay. At this
point I would think the switch and internal wiring is fine. I also
have one pin that has a very weak resistance to ground, not sure if
this should be there or not. Also, when I move the stalk to D I
can hear a click, I believe from the white relay mounted to the
motor itself (but I could be wrong). I do not get a click in any
other position. The wipers do not run in any position. The fuse
is good (checked with meter).

So, next I grabbed the wiper motor out of my parts car and plugged
it in. Predictably this one did not work either, but that doesnt
mean much since it's been sitting (also with a soda-bottle rain
shield) for probably ten years or more. However the wipers in my
driver worked fine until maybe January, I drove it and turned them
on and it took about 30 seconds and they started to run. Then the
next time I drive it they took a little longer to come on, but then
ran fine. Then they never ran again.

Questions:

What's the next step?

Where do I apply 12v and ground to bench-run it? Which combination
of the three wires on the white relay box should be turning it on?

Thanks!
Darel

 

i would check for resistance across the brushes at the pin itself. a multimeter should zero out if your brushes and internal connections in the motor are all good. then apply power wherever you get a good connection.

 

Assuming the wiper motor is the Lucas one with the wheelboxes and reciprocating cable to move the wiper arms, there is one possible fault worth checking.

The motor has an auto park facility that is activated by a ramp in the round casting on the end of the motor casing that contains the big wheel driven by the motor.

This autopark system actuates a small (about half inch square, quarter inch thick) sealed plastic part that contains a sprung contact. If you take this part off, you will see a small (about 2mm) "pip" that should spring back out when pushed in. The autopark pushes this in to stop the motor, but it should immediately spring out to reconnect current, so next time the wipers are switched on they work.

If this spring (sealed and invisible in the plastic part) fails, result, wipers will not work, even if current is fed straight into the exit wires from the motor casing. The motor WILL work if you can find a way to put current directly to the wires as they exit the comutator bushes, BEFORE they get to this little plastic part.

I only know this because I bought a NoS part which would not run at all after it moved half a turn. On taking it to bits I found this failure mode. Luckily I had an old motor in which this little part was OK.

Quite honestly, the easiest fix is to replace the Lucas with the later Electrolux system (post about 1988) from a scrap car. You lose the intermittent wipe, but the thing is much better and stronger.

Hope this helps

Greg

 

here are somepics of the part I mentioned:









The black pip should stand out about three times as much if the spring is OK.

Greg

 

M90: across which pins?

Greg: Thanks, I recall seeing that when I disassembled the motor last time. I'll have to check it out again to see if it's actually making contact or not. Wasn't really sure what it was there for because it doesn't really look like a contact.

Thanks,
D

 

OK, spent my whole morning going over this thing six ways from Sunday using both these instructions and Kirby's book. The motor still will not turn at all, not even a nudge or a quiver.

In addition to what I posed above, today I;

- Checked conductivity between commutator pads - all OK.
- Checked for conductivity between the pads and any other part of the commutator (steel core, shaft, etc) - all OK
- Checked the pin on the relay as Greg describes - it was fine.
- Swapped relays from my parts car motor (which also does not work) - no change.
- When I pull the stalk forward for the 1x sweep, I CAN hear that relay click in. I do not think the problem lies in the switch.
- Swapped cables from the firewall to the motor - no change
- Adjusted the worm drive preload screw thinking maybe it was binding the motor up - no change.
- Took the motor apart yet again, all nice and clean inside, commutator clean, brushes nice and springy and not worn down, magnets secure.
- Swapped out the fuse - no change

This motor makes no attempt whatsoever to turn not even a fraction of an inch. I can tell current is making its' way to the motor. I don't get it and I'll probably shoot myself if I have to pay $500 for a new wiper motor that I cannot even confirm is bad. I do wish I could bench-test it though - what pins do I apply 12v to? Since there are 3 brushes do I actually need to send 12v to 2 and ground one out? Ground 2 and 12v on one? Which ones get what?

Thanks,
Darel

 

Here is the diagram for a 1978. It may not be the same as yours, but check out what connections you need to make for the 'Slow' position. The way it works is that once running, the internal switch keeps the thing running until the driver switches off the motor whereupon the connections are changed, but the motor still keeps going until the internal switch is flipped to Park, whereupon the motor brushed are shorted to each other, and power is removed from the motor.

 

Sorry, slightly inaccurate. Power is supplied to the motor when the ignition is switched on, but goes nowhere until the driver wiper switch is operated. Essentially, it is earth switched.

 

i dont know a lot about this motor, but i do know that across a positive and negative terminal any motor with a good connection and good brushes will read about 0.0 ohms. also if you spin the shaft of any electric motor while checking the positive and negative terminals, it will act as a generator and the motor will produce a small amount of DC voltage.

bar none, the easiest way to check an electric motor.

 

If the motor has been checked by a professional I would make the assumption they knew what were doing (for the moment at least). So we will assume the motor is good until we can prove otherwise.

The operation is as follows in the slow mode you should have 12V on pin 5 of the motor and ground is pin 1. Both 12V and earth to the motor by the switch.

Firstly as with anything Jaguar CHECK ALL EARTH connections.

You should have earth on pin 4 constantly. Turn the ignition OFF and switch the wipers to low you should now have earth on pin 1, how much resistance do you have to earth here? Turn the wiper switch OFF.

Turn ignition switch on and you should have 12V on pins 1, 2 and 5 (yes its typical Jaguar put 12V on each side of the motor, BE CAREFUL with this). What happens is when you activate the wiper switch it then switches pin 1 to ground activating the wipers.

 

Thank you very much, here is some more info based on the above:

Ign on in slow mode I have good ground to 1 and 12v on 5. No run.

I have ground to pin 4 all the time. Ign off and wipers on low I have infinite resistance to ground on pin 1 = good ground.

Turn switch on and I have 12v to pin 1 but not to 2 and 5. Does this then mean a problem with my switch?

Using what you gave me above, I connected 12v to pin 5 on the motor itself and ground to pin 1. The motor did not turn. Where does the 12v from pin 2 go, does it open the circuit, ground it out, stay 12v? In order to bench test do I also need to send 12v to 2? If i could just get this thing to spin one time on the bench I'll start pulling the column apart right now, and happily.

Thanks so much for all your help!

D

 

As far as I can remember from school, if you take a 12v battery and put 12v plus to one commutator wire, and the battery - to the other, the motor should turn.

If it will not, then the field magnets are duff, or the brushes not connected, or the commutator not connected to the motor windings etc etc.

If yours will not turn when you put 12v across any two of the wires in my pics in the post I put up earlier, then my money is on the motor being duff for some reason. For sure if it will not bench run that is the problem, I reckon.

Greg

 

Ground to pin 4 is correct this is the motor park switch earth.

When you say you have infinite resistance this means high resistance = NO earth continuity = BAD.

You should have less than 1 Ohm to earth on pin 1. Can you report back back what the meter reads.

To bench test the motor put the Pos of the battery to pin 5 and Neg to pin 1 the motor should run

 

Not infinite resistance...000, full resistance. Good ground.

So, basically this motor is shot. Crap.

 

Have you bench tested the motor with a battery Pos to pin 5 and Neg to pin 1?

Also check the wiring between the motor and the connector.

 

Yes, I have. No run. That was what prompted me to come back and ask if I needed a second ground or a second 12v.

I've got blue, pink and (I think) yellow going to the motor casing itself. If I can even find a spot to do it, which of these 3 would get 12v and which would get earth? What would the third get? That'll be the real test - that bypasses all the contacts in the gear housing as well as the relay.

Thanks for all your help guys, even if I'm getting the answer I didn't actually want.

D

 

The wires colour codes are:
K= Pink
B = Black
W = White
G = Green
O = Orange

You should have 5 wires
KG = Switched earth this is pin 1
BG = Slow pin 5
WG = Fast pin 3
OG = park switch pin 2
B = permanent earth pin 4

I have checked this wiring on mine (although mine is a later model not cable drive) just to check the book was correct.

If your motor is US I would look at upgrading to the later arm drive. If you can find the whole grill assembly from a wrecker it should bolt straight up.

I can tell you they work much better than the older cable drive I had on my S1 XJ6.

 

Thanks but I want to try skipping everything but the motor itself (contacts in gearbox, etc), so I want to send power via the 3 wires coming directly off the brush plate - any idea how to jumper those 3?

 

Blue Yellow and Pink are different from what I have on my motor and what the book refers to.

I would assume Pink is earth this seems to be consistant with the book. The other 2 wires will be slow and fast as this is a 2 speed motor. So Battery Neg to Pink and Poss to one of the oter wires, just use a fuse in the Pos lead so you dont fry anything. Use a fuse the same rating as the one in the fuse panel. I am not at home so I don't have access to the fuse rating.

 

Figured out that blue (the one horizontal prong) was my earth and the other two are hi and lo speed. Oddly neither of my motors spins no matter what I do. Thing I don't get is, I went from 100% full function in all modes to zero function in all modes - this is why I'm dragging this out for so long.

I'm going to order a new brush plate since they seem readily available, and try the new brush plate in both motors, then if I still get nothing I'll bite the bullet and order in a rebuilt motor.

Thanks for all the help, guys!