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Thu Apr 30, 2020 1:21 pm

OK, first thing to do is map out the switch. This will be a bit tedious, but it's the only way to get this sorted out. What you want to do is, for every possible switch position, make a chart to show what switch wires are connected to that. While the four main wires (black 53, black/yellow 53b, black/white 53a, and green 53e) we can figure out from the schematic, it would be good to double-check them. It's the two remaining wires, S1 and Wash, that we need to know about. I assume you've added both of these to the switch.

Also: does your setup include the Bosch cube relay shown in the Photobucket drawings above which isolates the switch 'S' connection?

We'll go from there.

Thu Apr 30, 2020 1:36 pm

For the second part:

Yes, I used the second, Bosch style relay as described and laid out in those two diagrams.

It appears that an additional wire has been put into the harness to run the pump, but I cannot ascertain exactly WHERE the where is attached.

Thu Apr 30, 2020 1:51 pm

And the Bosch cube relay you used has the 87a terminal, which is connected to the 30 terminal EXCEPT when the relay is activated? (Some relays have 87a doing other things...)

Also: to include Ground in the switch chart!

Thu Apr 30, 2020 3:05 pm

To answer Telford's request for documentation of what each position does to each wire.

Switch off, wires connected to:
Ground:
Black, brown, black/green

Power:
Black/white

Nothing:
Black/yellow

Switch in slow position, wires connected to:
Ground:
brown

Power:
black
black/green
white
black/yellow(~7volts)

Switch in fast position, wires connected to:
Ground:
Brown

Power:
Black
black/green
black/white
black/yellow

Switch in Intermittant position (Level pulled position same):
Ground:
black/yellow (only when wipers not moving)
black (only when wipers not moving)

Power:
Brown (full time)
Black (only when wipers moving)
black/yellow (~7 volts only when wipers moving)

If I connect the pump wire to:
Brown: pump and subsequent 2-3 wipes works correctly. Intermittant does not work. I can hear a relay click as it is connected or disconnected.

Black: Intermittant works.
When I pull the lever, wipers and pump start running, pump pauses as wipers hit rest position then goes again for the full sweep. This action continues until the wires are disconnected.

Thu Apr 30, 2020 3:08 pm

telford dorr wrote: And the Bosch cube relay you used has the 87a terminal, which is connected to the 30 terminal EXCEPT when the relay is activated? (Some relays have 87a doing other things...)

Also: to include Ground in the switch chart!

Yes, that is correct. I just double-checked the relay.

Thu Apr 30, 2020 3:10 pm

Um, I was thinking of when the switch was totally disconnected from the bus. Sorry, wasn't clear.

Note: as we're trying to map the switch and it has a pins to a plug connection, then we need to map by the wire color that connects to the switch pins.

Thu Apr 30, 2020 3:15 pm

telford dorr wrote: OK, first thing to do is map out the switch. This will be a bit tedious, but it's the only way to get this sorted out. What you want to do is, for every possible switch position, make a chart to show what switch wires are connected to that. While the four main wires (black 53, black/yellow 53b, black/white 53a, and green 53e) we can figure out from the schematic, it would be good to double-check them. It's the two remaining wires, S1 and Wash, that we need to know about. I assume you've added both of these to the switch.

Also: does your setup include the Bosch cube relay shown in the Photobucket drawings above which isolates the switch 'S' connection?

We'll go from there.

Ok, I think I can go back and map out the switch to see what is connected to what.

Now here's my biggest question, perhaps, from what you are saying there.

My switch is the Champagne Edition switch. I have a total of 5 wires, the four plus S1 which is brown. If there is a different place to add a wash wire, I cannot figure out what exactly to add it to.

I have tried to add it to a couple places that it seems like it's been added in others' posts, but neither has worked right.

Thu Apr 30, 2020 3:18 pm

No problem - just map the added wires in their various positions.

Q: is the intermittent position connections the same regardless of the lever being pulled or not?

Thu Apr 30, 2020 3:37 pm

Let's concentrate on the brown wire and possible pump wire switch connections: map them to all the other wires and ground for all switch positions, and with the lever lifted or not. The four main wire connections look OK.

Thu Apr 30, 2020 3:54 pm

Switch removed from bus. Connections I found:

Fast:
black/yellow->black/white
brown->ground point

Slow:
black/white->black
brown->ground point

Intermittant:
Green->black

Pump:
green->black
black/white->brown

(I was surprised to see that black/white to brown connection in the pump setting but not intermittant setting.)

Thu Apr 30, 2020 4:13 pm

No, that's good. Note the brown wire connections: in the 'pump' position (lifted), the brown wire connects to black/white (e.g. 12 volt power); in the intermittent position, the brown wire is disconnected; all other positions it's grounded. This is the control signal the intermittent relay wants: +12 = 2-3 wipes, floating = intermittent (programmable or fixed); ground = normal wiper operation (see notes in the post above your first post).

We're half way there.

Now we need to find a pump drive connection. It will probably be grounded any time the switch handle is lifted.

Thu Apr 30, 2020 4:17 pm

These appear to be the two spots that the additional wash wire have been added to, from various pics in this thread.

Position marked as 1 goes to the black/white wire and the wash funciton just runs and runs.

Position marked as 2 is the rivet that the brown wire is attached to. Wash works when lever pulled, but intermittant does not work if the wire is connected.

Thu Apr 30, 2020 4:25 pm

telford dorr wrote: No, that's good. Note the brown wire connections: in the 'pump' position (lifted), the brown wire connects to black/white (e.g. 12 volt power); in the intermittent position, the brown wire is disconnected; all other positions it's grounded. This is the control signal the intermittent relay wants: +12 = 2-3 wipes, floating = intermittent (programmable or fixed); ground = normal wiper operation (see notes in the post above your first post).

We're half way there.

Now we need to find a pump drive connection. It will probably be grounded any time the switch handle is lifted.

The diagrams posted appear to show that the pump is already grounded, and getting power through the added wire.

Additionally, tapping the wire to a totally separate 12v source (e.g. fuse 12) will activate wash-running the pump briefly and then 2-3 sweeps.

Thu Apr 30, 2020 4:27 pm

vwwestyman wrote: Position marked as 1 goes to the black/white wire and the wash function just runs and runs.
OK, that's no good - ignore it.

Quote: Position marked as 2 is the rivet that the brown wire is attached to. Wash works when lever pulled, but intermittent does not work if the wire is connected.
Makes sense. The intermittent function needs the brown wire floating (unconnected). The pump will pull it to ground.

Is there any other connection which gets grounded when the lever is lifted but isn't connected to any other wire?

Thu Apr 30, 2020 4:54 pm

OK, my bad. We're looking for a connection which gets POWER (e.g pin 53a) any time the lever is lifted, and isn't connected to any other wire.

Thu Apr 30, 2020 5:04 pm

vwwestyman wrote: Additionally, tapping the wire to a totally separate 12v source (e.g. fuse 12) will activate wash-running the pump briefly and then 2-3 sweeps.
In this mode, does the pump run only when the wire has power applied, or will it run for a fixed period even if the wire is only momentarily tapped to 12 volts.
(trying to figure out if the "T" relay terminal will also drive the pump after being triggered, or if the pump only runs as long as power is applied to the pump).

Thu Apr 30, 2020 5:21 pm

telford dorr wrote: vwwestyman wrote: Additionally, tapping the wire to a totally separate 12v source (e.g. fuse 12) will activate wash-running the pump briefly and then 2-3 sweeps.
In this mode, does the pump run only when the wire has power applied, or will it run for a fixed period even if the wire is only momentarily tapped to 12 volts.
(trying to figure out if the "T" relay terminal will also drive the pump after being triggered, or if the pump only runs as long as power is applied to the pump).

The pump should only run when power is applied.

Thu Apr 30, 2020 5:21 pm

Pump only runs while lever is pulled, it quits as soon as you release the lever. Wipers start as soon as you pull lever, will sweep 2-3 times after lever is released and pump stops.

Thu Apr 30, 2020 11:03 pm

I don't know anything about bus wiper switches, but they do use the same relay as a '79 bug. So this may or may not relate to a bus switch but the brown wire on a bug switch is for intermittent function only, the green wire is for the park function not the pump. If your switch only has five wires I don't think it is capable of running a electrical pump. The switch that can handle both intermittent and an electrical pump has six wires. I think you are missing a red wire and it need to be connected to a terminal that makes contact to the black and white wire when you pull up on the switch.

Fri May 01, 2020 4:30 am

I would love to see a pic of exactly where this red wire is attached! Please!