Missing Wiper Relay

[flaflier]

In redoing my dash wiring, I have come upon what I believe is missing wiper motor relay. In comparing the wiring diagram with what I have, it appears that there should be a wiper motor relay between #59 and #56, of which there is a group of 4 orange wirenuts.



So my question is, can I wire it up without a relay, and just park the wipers manually, or is it preferable to use the relay. I know that the early cars (pre 266) didn't have a relay, and I am not sure exactly what to expect either way.

Anyone with a little more wiring knowledge than me on this issue, please chime in.

As far as the dash, I removed a 3-position switch (on-off-on), with low being down, and high being up. Should I replace with another 3-position, or should I try and source a rotary?

TIA,

Jim

[Grubby]

The ERA provided rotary switch is nice and matches the IP light dimmer. I would order from them.

I am sure Bob P. will chime in on the wiring question.

ERA 178 and 755 both automatically park the wipers. It is a nice touch.

John

[patrickt]

Originally Posted by Grubby

The ERA provided rotary switch is nice and matches the IP light dimmer. I would order from them.

I have both of those -- they look good. The "wiper relay" is really a little circuit board that is mounted on the driver's side of the firewall. You really can't miss it if it's there because it looks like a piece off an old smashed transistor radio. IIRC, it turns the wiper motor in to a generator momentarily to slam everything to a stop. I've probably turned my wipers on twice since I've owned the car -- and only just to see if they work.

[patrickt]

Here:

[strictlypersonl]

That's a little weird...

Earlier cars' wiper relay were only connected to the dash harness with a single 4-pole plug. (Very early ERAs used the original round switch with screw-on terminals. That switch is no longer available for anything close to a reasonable price.)
The other end of the early relay harness went through the firewall and connected directly to the wiper motor. I'm not sure what's going on with your car, since the relay appears to be completely missing. At any rate, you don't need the relay if you are willing to manually park the wipers. The wiring troubleshooting guide has information on what goes where, and why.

[flaflier]

My wiring is just like the diagram as shown by Pat, with 55 branching off from the front harness and coming down, connecting to 56, with no relay.

Bob,
Can I purchase just the switch (rotary) and the relay, so I can return to normal operation, or is the early wiper motor wired differently that it doesn't work with the relay?

Jim

[strictlypersonl]

It looks like that's not the original harness (judging from the connectors shown in the left side of the picture). The question is, do you have the wiper switch with the screw-on connectors? If so, I can make a connector that will interface with it to the current plug that connects through the firewall to the wiper motor.

[flaflier]

Well, my old wiper switch (below) was not stock...


Now my dimmer is as you described (2 screw), and is very nice.


So, what I was planning on doing was just obtaining a 3 position lucas toggle, and have it off-low-high. Then I would manually park the wipers..

Unless you have a proposition...

[strictlypersonl]

If you are willing to use a toggle switch (without automatic parking), your easiest/cheapest path is to get the toggle from Finishline (S W) and wire it directly to the motor. I don't have that switch's circuit diagram. Typically, terminal 1 is the power in.

[flaflier]

Thanks Bob,
That's which way I am going. I have already purchased the switch from finishline, and will self-park the wipers. The switch came with the wiring diagram, so that's done. Now I just need to get rid of the wire nuts.

On another note, I do believe the harness has been upgraded in the past, as it seems to match chassis 6xx on the diagrams, not the early ones. I have gone through the front harness, and once the dash is complete (soon), I will go through the rear harness.

Thanks again,

Jim

[flaflier]

Ok so I got the switch, but it doesn't seem to have 2 distinct circuits in the right order. I have 3 wires coming from the wiper motor, red, blue, and green. Red and blue are High and low, with Green being ground. Ground the green and put power to either red or blue, viola, wipers.

My question is does anyone know which lucas switch I can get that will operate the wipers so that the bottom position is off, middle is low, and top position is high?
It appears that the SW switch I have will go off in the middle, then turn the wipers on in either the up or down. I can also wire it so that the low is on in the middle, and high is the up position, but to do that, in the H position, there is power going to both H and L, and the wipers seem to not run at their fastest... don't really want to do that, I would expect something to burn out..


Jim

[patrickt]

Originally Posted by flaflier

I can also wire it so that the low is on in the middle, and high is the up position, but to do that, in the H position, there is power going to both H and L, and the wipers seem to not run at their fastest... don't really want to do that, I would expect something to burn out..

Use a relay, that when fed via a hot "H" line, breaks the circuit for the "L" line. IOW, if "L" alone is hot it flows uninterrupted through the relay, but if "H" is hot, regardless of whether the "L" is hot or not, the relay closes and breaks the "L" line continuity. Very simple to do.

[flaflier]

Any idea on which relay? (part #, mfg) I have spent the better part of 2 hours searching for such an animal, and have not found it... I like the concept, just need the relay..

Thanks, Jim

[patrickt]

Originally Posted by flaflier

Any idea on which relay? (part #, mfg) I have spent the better part of 2 hours searching for such an animal, and have not found it... I like the concept, just need the relay..

Thanks, Jim

I always just go straight to Mouser Electronics; they always have what I want and they ship fast. Here's a nice 12v 16amp SPDT relay for three bucks. RTD14012F TE Connectivity / P&B | Mouser If you want to bump the amperage up a little bit, or a relay that looks or mounts differently, just search around. I get their print catalog and it's wonderful -- about four inches thick, but great reading.

[strictlypersonl]

Is there a Lucas number on the Finishline switch? What are the numbers associated with the terminals on the back?

[flaflier]

Thanks, figured it out.
After looking at the switch, and usually using pin 1 for the common, I switched it to the 4 pin, and now the switch works as needed. The pin switch was instigated by my actually finding the directions that came with the switch!

[patrickt]

Originally Posted by flaflier

Thanks, figured it out.
After looking at the switch, and usually using pin 1 for the common, I switched it to the 4 pin, and now the switch works as needed. The pin switch was instigated by my actually finding the directions that came with the switch!

Reading the instructions is cheating.

[flaflier]

I know, I know... it was the option of last resort!

[strictlypersonl]

Real Men don't ask for (or read) directions.

That way we get to drive on roads we've never seen before, and meet tow-truck drivers we never otherwise would have.