How to bench test a Lucas wiper motor?

[my427cobra]

Hi all. I have a Lucas DR3 2 speed wiper motor (P/N 75309B) which I bought as a NOS unit (you should see the beautiful original old box it came in – a work of art) and will use it in my Cobra.

It has the 6 wires (Green/ power, Red/ B side brush, Blue/A side brush, White and Brown/ field wires, and Orange/Low speed).

I would like to bench test the motor, but of course the switch and harness are in the car.

How do I bench test this wiper motor to assure it runs on both speeds and which wires do I hook-up (I’m using a small 12v motorcycle battery to do all my wiring/continuity tests).

Any ideas or tips????

Thanks
Greg

[strictlypersonl]

From what I can tell from a diagram of the original 427 wiring, the green is connected to power. Sorry, but the diagram doesn't tell me much more, since it doesn't enumerate the connections to the rotary switch. And the rotary switch does some pretty complex things...

[HealeyRick]

Is this of any help: DR1 Motor The DR3 is at the bottom of the page.

[FWB]

step 1 should be have fire extinguisher available......

[Racer_X]

so from the schematic, 2&5 positive, 1&4 negative, 3 no contact for slow.
2&5 positive, 1&3 negative, 4 no contact for fast
to park, 1&5 positive, 2&4 shunted, 3 no contact, park switch closed.

[mickmate]

That diagram gives you the hook ups but the problem is getting a switch to drive it. They need a PRS7 which you can still get but the new ones have about 5 connections on the back the old ones have 13. You need all those connections to be connecting two at a time here and there and not having low and high speeds trying to run at the same time or you'll need the tool Fred said.

[my427cobra]

Thanks guys. Fire fighting equipment will be close at hand. May the smoke stay in the wires.

Greg

[Mongoose930]

I recently went through this same exact excercise. In order to make sure that your motor is working properly and that your wipers are parking, I would spend $20.00 and purchase the rocker switch from Finishline:

Finish Line Accessories

It comes with very clear wiring instructions and you will need to provide power both to the switch and the motor. I purchased one of the newer PRS7 rotary switches and was lucky enough to obtain a correct knob. I installed it in my dash so that it looks correct but it does not work. I mounted the Finishline toggle switch directly above the rotary switch and that is what I use to this day. I have searched and searched and cannot find a rotary switch that works with the two speed motor, parks the wipers that will fit in the dash and accept the correct knob.

Good Luck

[Three Peaks]

I bought a rotary wiper switch at NAPA made my Cole Hersee. It has four contacts on it marked "B", "P", "L", "H". I hooked it up to my 2 speed MG wipers and it works perfectly, including parking the wipers. I believe the part number is 75212-04 but I'll check on that if I can find it on their site or the Cole Hersee site. The nicest thing is it is only about $12 for the switch.

NAPA AUTO PARTS

Bob

[Mongoose930]

Thanks Bob - If you can confirm the Cole Hersee P/N, I will go out and buy one and look into what it takes to get the Lucas style mounting nut and knob onto it. I really appreciate the lead.

[Three Peaks]

Checked the number and edited my post. The knob with the switch has the sweeping wiper picture on it.

Bob

[Mongoose930]

Thanks Bob - I just ordered one. I will check the function and if all goes well, I will try to modify the bushing / shaft to use the Lucas mounting nut and knob.

[my427cobra]

Thanks to RacerX and his prescribed test hook-ups. Motor ran just fine in all modes with no smoke escaping from the component. All fire fighting equipment has been orderedd to stand down.


I thought I had every Lucas historical manual about wipers including this DR3 and including the original instructions included in the wiper box. Not one manual or document indicated how to do a bench test.

Thanks again RacerX.

Greg

[Racer_X]

Thanks to Rick Healey above for providing the schematic from which to interpret.

Greg, glad it worked out for you and it's all ok. now you can have peace of mind when installing it.
You're Welcome.
Curtis D.
otherwise known as RacerX

Originally Posted by my427cobra

Thanks to RacerX and his prescribed test hook-ups. Motor ran just fine in all modes with no smoke escaping from the component. All fire fighting equipment has been orderedd to stand down.


I thought I had every Lucas historical manual about wipers including this DR3 and including the original instructions included in the wiper box. Not one manual or document indicated how to do a bench test.

Thanks again RacerX.

Greg

[HealeyRick]

Originally Posted by Racer_X

Thanks to Rick Healey above for providing the schematic from which to interpret.

Curtis D.
otherwise known as RacerX

It's actually "HealeyRick", Rick being my first name and the Healey part is from the Austin-Healey that I'm just finishing swapping a 5.0L and T5Z into:





There's a lot of info I can get here that translates to my swap and I can occasionally return the favor with some knowledge gained in messing around with British sports cars for almost 45 yrs. There's some more photos of my build by following the link next to my sig.

[my427cobra]

Thanks for your help Rick. And your car looks great. I love those old Healeys. My next door neighbor has a fully restored 100/6.

Greg

[Racer_X]

My apologies, Rick. Nice Healey!
That thing oughta' scream when finished. Healey's are as light as Cobra's from the looks of it.

I remember the episode of Home Improvement when Jill bought her Austin Healey and Tim wanted to drive it.

Thanks, Curtis

Originally Posted by HealeyRick

It's actually "HealeyRick", Rick being my first name and the Healey part is from the Austin-Healey that I'm just finishing swapping a 5.0L and T5Z into:
There's a lot of info I can get here that translates to my swap and I can occasionally return the favor with some knowledge gained in messing around with British sports cars for almost 45 yrs. There's some more photos of my build by following the link next to my sig.