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Re: request for info on '80 B wiper motor

Subject: Re: request for info on '80 B wiper motor
From: (Denise Thorpe)
Date: Tue, 23 Jan 96 11:38:33 PST
Gary Burrell answered my question thusly:

> > From the drawing it looks like either 
> > the R/LG and N/LG wires are connected, or the G and U/LG wires are 
> > (the black wire goes to ground) but these don't work.  From experimentation 
> > discovered that power to the R/LG wire makes the low wiper speed work and 
> > power to the U/LG wire makes the high wiper speed work but neither of them 
> > would park.  I could make the low speed park by applying power to both the 
> > R/LG and N/LG wires and then removing the power from the R/LG wire.  But I 
> > couldn't find any combination of wires with/without power that would make 
> > high speed park.  Some of the combinations I tried made my jumper wire very 
> > hot.

Interesting side story:  When I was trying different combinations of wires, 
I was holding the the bare ends of wires between my thumb and forefinger.  I 
knew that as long as I wasn't grounded I wouldn't get shocked.  But when I 
was washing the grease off my hands later, I discovered that the ends of all 
my fingernails were yellow and folded under.  =:-O

> Well Denise,
> I'm going from memory on this but my 68 has a two speed motor, and I 
> played with fixing it this summer.  (I don't know if it matches the 80 
> motor).  

The Moss catalogue only lists two wiper motors so I think '68 on should 
be the same.

> The switch has three positions.  None of which are "off" or 
> open.  Call these positions, Park,low and high.  4 wires go to the 
> switch, power, low, high, and park-power.
> the switch then works as follows
> Park: connects park-power to low wire.  Park power cuts out when the 
> motor hits the park switch.
> Low: connects power to low side.
> High: connects power to high side.
> The motor has 5 connections.  Ground, power, low, high and park-power, 
> the park switch connects power to park-power until the motor hits the 
> park position.  Unless your wipers are parked there should be a very low 
> resistance.

Ah HA!  I was assuming that each speed would have its own park wire.  That 
was dumb because park is park and 12 volts is 12 volts.  Now I get it, the 
solid green wire is constant hot like the green wire in my '67 and the 
N/LG wire is park for _both_ speeds.  (Jerry Causey- this Brown w/Light 
Green wire needs power when the switch is in the "off" position.)  Now all 
I have to do is find out how to get power to the appropriate wires at the 
appropriate times from a pre-'66 headlight switch.

When I was trying to figure this out last weekend, I put the one speed wiper 
motor in my '67 through its paces and discovered that both wires get power 
as soon as the ignition is turned on and the wiper starts working when power 
is _removed_ from the Green/Light Something wire.  The car already has the 
headlight switch installed where the wiper switch used to be.  I did this 
when the wiring harness burned down sometime in '83.  I don't remember what 
I did then and I have no idea why my wipers work now, but since they do, the 
headlight switch must have the correct connections to work with a wiper motor 
that gets power when headlights don't and vice versa.

When I'm done and everything works as advertised, I'll post the procedure in
case anyone else wants to do this.

Thank you Gary! :-)

Denise Thorpe
'67 B, BRG, one-speed wipers with headlight switch, daily driver,
'67 B, originally BRG, now burgundy w/bondo pink, will be OEW w/beige,
  restoration project and wiper assembly donor,
'63 MG 1100, black w/red, used to be a hillclimb racer, still driven regularly,
'63 MG 1100, dark dark green w/grey, living in my backyard,
'65 MG 1100, black w/red, still hoping to go to PA.

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