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Re: 3-Position Wiper Switch

To: "mgs" <>
Subject: Re: 3-Position Wiper Switch
From: "Denise Thorpe" <>
Date: Tue, 11 Sep 2001 18:37:47 -0400
Hi all,


I don't seem to have gotten the original of this.


Anyway, this switch is exactly what I have operating the two-speed 
wipers in my '67B.  It's the headlight switch to the '62-'65 B, which is 
more readily available than the '67 headlight switch.  A long time ago I 
posted the entire process for this conversion and then lost the 
original email and forgot what I did.  Enough people have asked me about 
this that I asked the list to steer me to the archives so I could recreate the 
instructions.  I found the original posting, but it no longer made sense 
even to me.  It's on my list of things to do to figure this out again and 
rewrite it more intelligibly, especially since I need to perform this 
on my '63 MG 1100's.  But for now, here's the original post.  Ignore 
the ASCII art.


BTW, the B is running on a loaner generator from Steve Devine, president of 
the Boston Area MG Club.  Thanks!  And thanks to everyone who 





This is the procedure for installing two-speed wipers in a US-spec MGB that 
originally came with one-speed wipers (pre-'68).   

Parts:  Two-speed 
wiper motor with electrical connector and mounting bracket, '68 and later. 
Toggle headlight switch for '62-'65 MGB, TRF #LU31837, Victoria British #8-414, 
Moss #141-230, sheet metal and bolts for custom mounting bracket, assorted 
and connectors   
Before mounting the motor, some modifications need to be made 
to it:  The two-speed motor was used 
on cars with three wipers.  The 
drive cable for these motors is shorter than the two-wiper cable.  The cables 
are mounted differently in 
the two different motors so just the cables should be switched.  With the flat 
cover removed from the 
motor, the procedure should be obvious.  
While the cover is off and the cable disconnected, the position of the 
cable on the gear relative to the position of the park switch needs to be 
changed.  The wipers on three-wiper 
cars park the other direction so the park direction needs to be reversed.  To 
do this, remove the circlip holding 
the large (2" diameter) nylon gear to the housing and remove the gear 
assembly.  You'll see two square 
bosses on the gear that fit into two square cutouts on the metal plate.  Pry 
the gear away from the metal 
plate.  When the bosses are clear of 
their slots, turn the gear 180 degrees and line up the bosses.  Press the gear 
back towards the plate 
and re-install the assembly.
Mounting the motor:  
The early wiper motor is mounted to a black bracket with studs that screw 
into the upper part of the motor (where the cable goes in).  The later motor 
doesnt have these 
threaded holes.  It's mounted 
directly to the firewall (I assume) with a strap that goes around the lower, 
round part of the motor where the windings are.  I made a sheet metal plate 
(out of a 
rusty battery cover) that mounts to the early bracket where the motor studs 
and extends down and to the left (LHD car).  The motor is then mounted to the 
with the strap.  Here's an ASCII 
drawing of the plate:            

() | This is where the early motor was mounted            
| ()               
| with big rubber bushings.           
() |           
|   ________|                  
|   |                          
|   |                          
|   |                          
|   |  o                    
o  | The strap holds the 
motor to the plate here.   
| Packing needs to go under the motor to make the    |                          
| strap tight.   

This method uses both early and late mounting brackets plus a 
custom bracket.  It should be 
possible to mount the later motor the way it was mounted in later cars using 
only the strap.  I didn't do this 
because it would require drilling holes in the firewall.  If you choose to do 
this, you'll notice 
that the motor is too far away from the firewall.  It should be possible to fix 
problem by bending or replacing the cable sheath between the motor and right 
side wiper.   
Wiring:  The 
switch logic is: 
Connects terminals 
The connector to the two-speed motor has five 
1       | 
3  2   |  
5  4   |
 The wiring to the motor is:
1 is black (B) - ground 
2 is brown w/light green (NLG) - park 
3 is blue w/light green (ULG) - high speed 
4 is green (G) - keyed power in 
5 is red w/light green (RLG) - low speed  
The wiring harness in my '67 B has three wires at the wiper 
green (G) -  
keyed power in 
black w/green (BG) - to the switch 
black (B) - ground  

To wire the two-speed switch in a '67B, the green and 
black wires from the harness connect to the green and black wires at the 
motor.  I used the black w/green 
wire (BG) in the harness for the high-speed wire that should have been blue 
w/light green (ULG).  Additional 
wires came from a partially burned harness so I had the correct color wires 
for the other two wires.  The colors listed 
here match the colors listed above for the motor so even if you don't have 
the original color wires, you can wire correctly by connecting the 
switch terminals and motor connector terminals of the same listed colors.  
At the switch when it's in a '67B, the wiring is: 
4 - green (G) 
6 - red w/light green (RLG); jumper wire to terminal 1 
8 - blue w/light green (ULG), or if using the harness wire, 
black w/green (BG) 
1 - jumper wire to terminal 6 
2 - brown w/light green (NLG) 

----- Original Message ----- 

From: Max Heim  

To: MG 

Sent: 9/9/01 9:44:22 PM 

Subject: Re: 3-Position Wiper 

The headlight toggle switch is a 3-position switch. Maybe you 
could figure

out how to wire one of those?


on 9/8/01 6:32 PM, Jerry Causey at  


  I've replaced the single-speed wiper motor in my 1967 

  with a later two-speed wiper motor. Does anyone know 
where in

  the USA I can obtain a 3-position toggle switch which 
was used on

  the 1968 UK spec (metal dash) MGB?



  Jerry Causey





Max Heim

'66 MGB GHN3L76149

If you're near Mountain View, CA,

it's the red one with the silver bootlid.


--- Denise Thorpe




--- Denise Thorpe


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