DR3 Wiper Motor Wiring


I have a 1958 XK150 FHC. I need a little help with wiring the wiper motor. This will be easy for someone.

The first 2 pics are what I have. Notice the wires are black from the years and are not colored. I dropped the dash and individually rung each wire out and labeled each based on the wire attachment connector on the switch.

I have the 3rd picture, wiring diagram which is very close to what I think I have.

[[WHY are the wire descriptions backwards?? Are not wires called out by the PRIMARY color followed by the TRACE color or the STRIPE color?? Green with a white stripe is GW!! What gives??]] (Rant over.)

My wiring difference, I also have wires:
8 - motor body ground
9 - additional wire from 1 to wiper motor.

1 In the above wiring dwg, wire 7 is to W. What is W?
2 I have a Switch terminal No 1 wire out to the motor. Is this correct? (Not correct per the dwg but…what is this for)
3 If No 1 wire is to the motor, where/which wire is the connector?
4 I don’t have a wire from A4 fuse to motor G. Apparently I need to run a new wire. I find it strange I don’t have an A4 wire, hence my reluctance to complete the wiper motor wiring.
5 COULD the wire from Switch No 1 be the A4 wire? (I don’t know what 1 is for.)

Thanks much for any help.

Hi Tim, Terminal ! should be a black wire to earth, don’t know where the W came from.
Wire from Fuse A4 needs to power the motor, don’t know where wire 9 is connected but should go to earth same as wire !.
I am looking at wiring diagram from Coventry Auto Components, very helpful wiring diagrams. A4 terminal is located at fuse 6, a 50 Amp fuse located in the SF6 terminal block. John

I installed the new wiper motor. Dropped the dash, checked all the wiring from the switch to make sure what I have labeled is correct from the switch to the 10 way connector. I labeled the wires as they are all the same color; aged, dirty, black and unrecognizable.

Key on, no smoke, switch on and nothing. Gas gauge needle no longer moving so I assume I blew a fuse. Correct assumption.

So let’s start. I don’t understand the switch to wiper wiring. I have NEVER seen a motor independently wired outside of the switch. This doent not make sense to me. All other cases that I can think of power goes to the switch and the switch powers the motor; the heater fan. Can someone explain why this is different?

Also, I would like to put power to just the wiper motor and wire from slow to fast. How do I do this? To determine the wiper motor is OK
How would I check the switch? Procedure?

Thank you


First of all, I assume you’re referring to the DR3 and that DP3 is a typo.
I also had many questions when I rebuild my DR1 motor for an XK 140. However, there is one JL member (Eric Capron) who did a lot of research on these DR1 and DR3 motors and wrote a technical story on the subject. You will find that here:

I also remember that the type of wiper switch used (either PRS5 or PRS7) will influence the wiring connections. Best would be to read Eric’s article and check every item of your system.

I also read in his document that connection 2 on the wiper motor (connected to the white wire in case of the PRS7 switch) is running to the Field Coils and if connected to 12 V that should turn your motor (if the housing is connected to mass of course).
I see in your drawing, however, that connection 2 is connected to the red wire and that connection number 1 is connected to the white wire. There is something incorrect here…
Finally: the DR3 has a “thermal cut-out” that stops the engine when overheating occurs. That could be another cause why your motor doesn’t work. But again read the story and check every item.

Bob K.