Intermittent wipers on an early 911

mjshira · 08-20-2006, 10:08 AM

As some of you guys know I have been busy doing the complete interior on scruffy. Since Tyson did the engine and trans and I finally purchased a home and have a garage (oh how sweat it is!) I began to remove the interior of scruffy and replace it so that that the new mechanicals and paint would have the nice interior to match.

One of the last things I need to do is add the wiper delay switch I purchased. These were standard on later model 911's and I thought with the dash out and blower motor out I could make quick work of adding one.

Well, turns out for a novice like myself this is not that easy.

Does anyone have a wiring diagram that they could post?

Thanks in advance

Here is a shot of the direction I am going with the dash.

randywebb · 08-20-2006, 10:19 AM

"oh how sweat it is!"

- how true

- I don't have a diagram, but you might compare the one for newer cars with the int. switch std. with yours. Pano had a summary article on wipers so there should be an UpFixin' on it.

mjshira · 08-20-2006, 10:29 AM

thanks Randy, this is an older pic, I left the camera at the office else I would post some newer ones. all the factory switches are replaced by toggles (69's vintage) and the cable pulls for air will be hidden up under the new dash (which is a modified version of what you can buy from rennline)

DW SD · 08-20-2006, 10:55 AM

James,
Looks good!
Did you replace any of your gauges? I'm seeking a temp sender and matching gauge for my car. Currently, the gauge is from an '86 3.2, but could change

Thanks,

Doug

mjshira · 08-20-2006, 11:13 AM

thanks Doug

All the gauges have been gone through by NHS complete with LED conversion. I had the clock switched to AMP meter/ Trans temp. I have some extra gauges laying around, let me know what you need.

Right now I am fighting the wiring issues. As this car was converted to late carrera dash and switches, etc, I have now switched it back to early. moving switches to toggles has been fun!

So any help you guys can offer would be greatly appreciated.

73911guy · 08-20-2006, 01:23 PM

Jim

Most people on the left coast don't understand how "sweat" it is to have a garage in Heavensville, Indiana.

Last evening it was overcast and the heat index was still over 105. It has kept me from doing anything in the garage for a month or so. I know, I'm a wimp.

Good luck on your car.

Jim Dasher

mjshira · 08-20-2006, 01:28 PM

Jim, glad to know you knew my meaning ;-) drop me a PM sometime. However, today is not that bad out there. This summer has been rough in the shop. I do have a fan but it really can't move the air enough.

RoninLB · 08-20-2006, 02:10 PM

mjshira · 08-20-2006, 02:55 PM

thanks Ronnie!

I might be back in NYC soon, I'll keep you posted!

RoninLB · 08-20-2006, 03:21 PM

the wiper delay diag is for '76,'77.

mjshira · 08-20-2006, 03:25 PM

I just purchased the relay so I can install it, thanks.

Walter_Middie · Walter_Middie's Garage

I hope the following matches what Ronin sent you - or else it will get confusing - this is what I have in my 1975.

The wiper switch consists of terminals # 53a, 53, 53b, 53i, 53e, and 53c. During wiper park cycle, 53e (blue wire) is connected to 53a (red wire, +12 v all the time), and this allows the wipers to continue to move until they get to the park position. The connection is made when the wiper switch is off and the wiper motor is not in the park position. The wiper motor makes the connection between 53e and 53a with an internal disk. The wiper switch connection between 53e and 53 puts the wipers into the slow mode, until the disk inside the motor turns to the park or off position.

53a Red = +12 v all the time
53 Red/Black = slow speed wipers
53b black/yellow = medium speed wipers
53i green = fast speed wipers
53e blue = park at slow speed
53c black = washer pump motor

mjshira · 08-20-2006, 03:53 PM

thanks. I am going to have to add a relay it seems and then figure out how to splice it all together.

Uwon · Uwon's Garage

I’m resurrecting this very old thread as it deals with the issue I’m having installing a potentiometer for the windshield wipers on my ‘71 build.

I’m pretty much a novice reading wiring diagrams so please bear with me.
Blue circle-is this part of the relay? What is it?
Red circle-is this also part of the relay? What is it?
J31- relay- my understanding is that this relay is no longer available. Is there an alternative like a normal Porsche relay and if so, what would be the revised numbering system on the wiring?
TIA,
Cheers,
Johan

Uwon · Uwon's Garage

Bump.

spuggy · 03:14 PM

Quote:

Originally Posted by Uwon

Blue circle-is this part of the relay? What is it?
Red circle-is this also part of the relay? What is it?

Photos of the used relay show that it has 7 pins.

Looks to me as though both the blue and the red circles are part of the relay - count the connections of both - there are 7...

There's a transistor shown inside the relay, so I'd guess that the unknown other component is a capacitor - part of the delay circuit, along with the transistor.

Quote:

Originally Posted by Uwon

J31- relay- my understanding is that this relay is no longer available.

Our host lists it as available from "OE supplier" Porsche Pulse Wiper Relay

as well as "Genuine Porsche": Porsche Intermittent Wiper Relay - 91161814902 - Genuine Porsche

And a non-OEM, non-Porsche variant Porsche Intermittent Wiper Relay - 91161814902 - Flosser 162917

Other sources list it as new, and there are, of course, used ones.

You might also want to consider the factory wiring harness also - might make it easier to just plug it in/connect it all up. Looks like the 74-75 and 76-77 and up to 1989 cars may have used a different approach through.

Quote:

Originally Posted by Uwon

Is there an alternative like a normal Porsche relay and if so, what would be the revised numbering system on the wiring?

Normal relays don't contain intermittent delay functionality. I'd guess it's less work to graft the later wiring & relay to an earlier car than implementing your own intermiitent delay circuit.

76FJ55 · 05-26-2025, 03:38 AM

yes, both items circled are part of the relay.

the blue circle is the electro magnetic coil. when there is power flowing through this coil it becomes a magnet and pulls on the item in the red circle.

the red circle is the high current switch within the relay. when there is no power going to the magnetic coil (blue circle) the switch is in its normal position and connects terminal 53 to 31b. when the magnetic coil is energized the switch is pulled towards the coil and toggles to connect terminal 53 to 15.

Since you asked initially about the potentiometer, it is Item E in the diagram with terminals 15, 15a and 15b. it consist of a mechanical switch connected at 15 which when open turns the intermittent wipers off. when closed it supplies power to 15a and to the input side of the rheostat. the rheostat then has a wiper which varies the resistance between 15 and 15b to adjust the voltage boing to the relay on 15b, which the relay uses to control the intermittent wiper timing.

Uwon · Uwon's Garage

Thank you Spuggy and 76FJSS for your replies. Very helpful. I found a relay and wiring from an ‘88 (I think) and will attempt instal now that I have this new info.
Cheers,
Johan

spuggy · 05-27-2025, 09:10 AM

Quote:

Originally Posted by 76FJ55

Since you asked initially about the potentiometer, it is Item E in the diagram with terminals 15, 15a and 15b. it consist of a mechanical switch connected at 15 which when open turns the intermittent wipers off.

I bought a spare pot, but when I went to fix my intermittent wipers, I found that a soldered connection to the switch had failed due to the unsupported part of the wire work-hardening and breaking off there. 90 second fix, took longer for the iron to get up to temp...

IIRC, the part is a panel-mount 100K logarithmic pot with on/off. Porsche ones are expensive, but that's a $5 part...