Converting to 2-Speed Wipers
As of:  6 December  2002 

        After seeing discussions on several internet BBS's about upgrading older MGBs with single speed windshield wipers to the later two speed ones, I decided to tackle this project. I had previously been made aware of instructions on how to do this, but after checking them out could see that the wipers wouldn't park when the switch they used was turned off. So, I did quite a bit of research, circuit testing, wire tracing, and consulting and have came up with an instruction package for you.


 wipers-WIPERPARTS1.jpg (20925 bytes) The first thing you'll need is a 2-speed wiper motor and attachments that can be obtained from anyone who salvages MGB's. Tony Barnhill, of this site has several, and the picture shows what you'll need. The wiper motor (2) and park switch (11) will be assembled when buying a used motor. You'll also need the mounting strap (13), rubber pad (14), and spacer block (15), along with the ferrule (21). Get the mounting bolts too if they'll send them.
 wipers-WIPERSWITCH1.jpg (6359 bytes) The second thing you'll need is an in-dash wiper switch that will park the wipers properly when they are turned off. It took a few days of research, but I found one (and only one) in-dash switch that will do the job. It's a Cole Hersee #75212-04. The knob on this switch is about 1" in diameter and will blend in well with it's surroundings, especially if you mount it where the old wiper switch is now.


         If you don't have a fog light switch you may want to consider mounting your old wiper switch in that hole just to get a balance of toggle, knob, toggle across the dash. That would make the knob fit in quite nicely; or, you may be able to find a smaller knob that will fit the switch. This switch will most likely have to be special ordered so make sure you can get it before doing anything else on this project.

        Cole Hersee is the industry leader in big truck switches and other electrical items, and their products are available only from heavy truck dealers and parts suppliers; they do not sell direct to consumers. Check your yellow pages for heavy truck dealers and parts suppliers. A source for a similar switch, but it has a "push the button to wash" feature, is Jeg's High Performance Parts. See the actual switch at this link:  This switch is actually obtained from Painless Wiring #80713, and they get it from Cole Hersee. The Cole Hersee switch #75212-04 does not have the push to wash feature nor that icon on the knob.
The last thing you'll need is wiring between the switch and the motor. I started out with a couple of ideas about how to accomplish this and didn't like either of them. First, auto salvagers don't like to cut up harnesses, and even if one did you'd still have a lot of work to do. By the time you buy all the fittings and rolls of colored wire you'd need you would be out at least $30.00 and still have to figure everything out and wire it up; not good.

        So I made an arrangement with British Wiring phone 708-481-9050 to make up a harness for this job. Contact them, ( I dealt with Ed) and ask for "Small Wiring Harness #423". They said it costs $23.00, that's a lot less than you can make one that's not proper in the end. This #423 harness has the plug for the wiper motor and 4' of the proper color coded wires with shielded female spade connectors for attaching to the switch. There is also a short black ground wire with an eyelet on it.

NOTE:  Always disconnect the battery before doing any electrical work on a car.
 wipers-WIPERSWITCH2.jpg (36981 bytes) This illustration of the back of the switch shows how the wires of the harness are connected to it, and there are only two other connections to be made. The eyelet on the black ground wire goes under any handy screw on or near the motor that is grounded. You will find a solid green wire to your old motor plug and it gets tied in (attached to) the solid green wire in the new harness.
On some models the solid green wire may be a green/pink one. That's OK, they both do the same thing and changes nothing about the operation of the wipers.
 wipers-SCOTCHLOCK.jpg (36087 bytes)  Just connect it near the motor with a quick splice, commonly called a 3M Scotchlock and the blue ones are the right size for this job. If you want to leave your old plug installed that will be fine, but you'll have to do a little work on the Scotchlock to make it work well. Open the Scotchlock and look inside, you'll see that the back wire channel has a stop in it. That's there for the way this splicer is normally used to tie a wire into a circuit. Since we're running two wires completely through we'll need to cut that little stop out of the way and tape up the original plug so it's contacts can't short to ground when it's tucked out of the way. Just place the two wires in the channels, close the Scotchlock, squeeze the metal piece down over the wires with common slip joint pliers, and snap closed the insulating cover.
        While the motor is out of the way you'll need to remove the windshield wiper arms, pull out the drive cable and remove the ferrule and install the proper ferrule, (21) above, and slide the cable back in. You may want to lightly lube it with light grease like maybe Lubriplate 105 if you have it. Heavy greasing of this cable could cause the wipers to run more slowly in cold weather when the grease stiffens up.
        When everything is installed, (except the wiper arms), re-connect the battery, cycle the motor a couple of times, turn the switch off, and reinstall the wiper arms. That's it, we're finished.

John Dandy
(theAutoist NOTE:  John Weimer's new "nom de plume")