Fluted rotary wiper knob - park facility

KevinW · #1 (**permalink**) 01-28-2010, 04:38 AM

I am planning on buying a set of the correct fluted wiper knobs for guys in the UK. The issue now is the switch.

I think the correct Lucas part no. is: PRS-7 54033632 or part no. 39156.

Heres 1 i found on ebay (now sold):
http://cgi.ebay.it/lucas-54033632-39...2#ht_500wt_949

The issue Im worrying about is how to implement a park function for the wipers as I think this is an Off-On-On, and I think I need a swicth with On-On-On.

Any good solutions, or is the answer 'originals didnt have a park function on the wipers'?

Kevin

strictlypersonl · #2 (**permalink**) 01-28-2010, 04:57 AM

The original rotary switch had the parking circuitry built in, but the NOS disappeared a long time ago. We use a Lucas 54033632 with a special relay board. Without the board, no parking function.

Woodz428 · #3 (**permalink**) 01-28-2010, 05:39 AM

Quote:

Originally Posted by strictlypersonl

The original rotary switch had the parking circuitry built in, but the NOS disappeared a long time ago. We use a Lucas 54033632 with a special relay board. Without the board, no parking function.

It's been a few decades since I owned some Lucas electrics, but I find that interesting. Most american wiper motors, at least those I've worked on, have the park built in to the motor. When you shut it off it cycles back to where the current ends...so to speak.
I'll have to check how the Coupe wiper system works.

mickmate · #4 (**permalink**) 01-28-2010, 05:44 AM

I believe there is a brush contact in the original motors. When you switch it off it keeps the motor energised till the park position is reached and breaks it there.

strictlypersonl · #5 (**permalink**) 01-28-2010, 08:04 AM

Quote:

Originally Posted by mickmate

I believe there is a brush contact in the original motors. When you switch it off it keeps the motor energised till the park position is reached and breaks it there.

Not quite. A circuit is temporarily created that's supposed to turn the motor into a generator (through a grounded circuit) to quickly stop motor rotation.

KevinW · #6 (**permalink**) 01-28-2010, 08:26 AM

Thanks for the replies so far.
The two issues I was trying to raise (probably expressed badly) is

- whether you need an On-On-On switch, or On-On-Off,

and

- whether the switch I linked to would do the job ie park the wipers fully horizontal automatically when wiper swicth turned to 'off' position.

I think, but Im not sure, that the answer to the second question is No without a relay board, with jury still undecided on the first question?

.... so i guess I have to ask .... where do I buy, or how can I wire up a suitable relay circuit (I can implement sraightforward electrics/electronics)?

Kevin

strictlypersonl · #7 (**permalink**) 01-28-2010, 05:55 PM

There are a bunch of threads covering the wiper circuit over on ffcobra.com. The toggle switch they use has a similar connection function as the rotary switch. Essentially off/on/on. Just to make things complicated, there are also a couple of different styles of wiper motor.

FatBoy · #8 (**permalink**) 01-28-2010, 11:08 PM

Quote:

Originally Posted by mickmate

I believe there is a brush contact in the original motors. When you switch it off it keeps the motor energised till the park position is reached and breaks it there.

That is correct. There is no circuitry required on the switch. All it needs is a swith that will provide an On-On-On facility. The first On position is really the Off position, but it provides an alternative live feed to the wiper moter, which is broken automatically at the motor by a cam when it reaches a pre-defined position.

My Kirkham was supplied without a park facility on the wipers and I've since rewired to to self-park. There was no additional circuitry required for the switch.

Paul

westcott cobra · #9 (**permalink**) 03-25-2010, 05:22 AM

A Rover P6 Wiper switch has the same turn-on design as the original Cobra switch, two speed function, a push function for washers and in some cases a intermittent position. I bought some via ebaymotors.co.uk.

They are availlable from time to time...

For the fluted knobs i bought blank knobs from the UK and gave them away for engraving. See here:
http://www.clubcobra.com/forums/atta...5&d=1235125750

Westcott

mickmate · #10 (**permalink**) 03-25-2010, 05:37 AM

Hey Kevin is that switch on,on,on do you know? If so that will work.

mjhcobra · #11 (**permalink**) 03-25-2010, 07:08 AM

I am in the midst of installing my wiper assembly and searching for the correct switches also. I am using the Lucas 14w motor found on Triumphs, MG's, and Mini's. On the 14w, the park switch is mounted on the motor. I currently am using a Lucas toggle switch 35927 and the motor parks each time the switch is shut off, but I need to know which rotary switch will perform the same as the 35927 toggle.

Any input will help. Martin

westcott cobra · #12 (**permalink**) 03-26-2010, 07:05 AM

Martin,

i will have a look on part numbers this evening and communicate them here.

Westcott

Gonch · #13 (**permalink**) 03-28-2010, 09:25 AM

I dont suppose anybody has found during there research a fluted knob with the 'PRESS FOR WASHER' engraved into it, like the attached pic?

westcott cobra · #14 (**permalink**) 03-29-2010, 01:33 AM

The switches i use have the following part numbers on the original boxes:

- 39 195
- 39 796

Both have a push washer function, not existing in the original switch, but i like the possibility to have a "hidden" washer funtion with the original look just in case....

The positions have the following internal functions:
OFF- curcuit closed for the park power
#1 - curcuit "OFF" cutted, circuit to #1 closed
#2 - circuit #2 closed
push- washer pump circuit closed

If you switch to park the 2 speed circuits are cutted and the OFF is closed again. The plastic park switch clipped to the Motor cuts the park circuit when a small bump on the motors big plastic gear lifts the contact tongue in the park switch in the defined park position.

Westcott

FatBoy · #15 (**permalink**) 03-29-2010, 05:13 AM

Hi Westcott,

Are they Lucas part numbers?

Thanks,
Paul

mickmate · #16 (**permalink**) 03-29-2010, 06:32 AM

The switch is indeed a Lucas PRS7 39156 in the originals. I think it will only work correctly with the DR3 motor though.

westcott cobra · #17 (**permalink**) 03-29-2010, 10:21 AM

Paul,

these are the original Lucas Numbers printed on the Lucas boxes.

Mickmates switch is actually on Ebay UK:
http://cgi.ebay.co.uk/lucas-54033632...30207002r13435

Uwe

FatBoy · #18 (**permalink**) 03-29-2010, 10:36 AM

Yes, I've been in touch with AES this afternoon. As it happens, they are only a few miles from me.

Can you confirm that this switch will work with the self-park switch in the wiper motor?

Thanks,
Paul

westcott cobra · #19 (**permalink**) 03-29-2010, 10:49 AM

I have no knowledge about the internal functions of the 39156, i allways try to build "budget", therefore i came after the P6 switches.

Just ask the seller if the switch will work with your wiper motor.

Greetings from Germany, Uwe

mjhcobra · #20 (**permalink**) 03-29-2010, 02:47 PM

I am looking for the lucas rotary switch that works with the lucas 14w motor. If a lucas switch with the push button for the squirters works, I will use that one.
Uwe, you provided two part numbers, are they both the same switch with different numbers?

Also, any ideas on the fresh air knob and cable?
Thanks, Martin