So he was using a relay with 2 form A contacts?

Check the BE section of the FSM.

The service manual only gives you the electrical schematic and doesn't tell you which wires have power in the different modes. Maybe Dave can share that information. Is it the same for all S30, like a 280Z?

The service manual only gives you the electrical schematic and doesn't tell you which wires have power in the different modes. Maybe Dave can share that information. Is it the same for all S30, like a 280Z?

With some studying of the wiring diagram, that could be figured out.

For instance let's look at the switch.

From the attached image we can determine the following connections at the different switch positions:

Off

LY - YB

In

LY - YB

YG - WR (12VDC)

Low

WR - YB

WR - YG

High

WR - LY

WR - YB

Tracing those wires will probably take us over to the amplifier circuit. From seeing what connects where and the other diagram in the BE section, we can probably figure out the function.

The service manual only gives you the electrical schematic and doesn't tell you which wires have power in the different modes. Maybe Dave can share that information. Is it the same for all S30, like a 280Z?

Isn't that what page BE-65 in the 78 FSM shows?

You can trace the lines on the wiring diagram to the amplifier unit, but unless you are an electronics engineer, that's as far as you can go. There is even a symbol in the amplifier schematic that I've never seen. Even the name "amplifier" seems misleading, as that unit turns on the wiper motor when you turn the switch or activate the washer pump, and it has a timing section to make the motor run intermittently. It looks like it's acting as solid-state relay (with a timer function for the intermittant thing.) May one of our engineers here could look into it to design an equivalent or a better one. So unless you get out a scope and splice into the motor's harness, you won't otherwise be able to see what is happening when you turn the switch.

Just from the looks of the amplifier design (of the 280Z wiper amplifier) and the amount of current it's probably controlling, I'm inclined to think the problem with slow wipers is partially in the connectors and partly in the old parts inside the amplifier.

Edited May 27, 201113 yr by TomoHawk

TomoHawk, I understand what the OP, hogie, and everyone else in this thread is discussing and trying to accomplish but you probably need to start your own thread since your questions don't involve a 240Z, a Honda wiper motor or the upgrade relay setup. Just sayin'.............

You may be right. I was thinking that the upgrade relay system could be adapted to a 280Z, but there is a lot of research to do, beginning with the 240Z stuff.

The need for a wiper motor upgrade is really more of an early S30 problem. The wipers were actually pretty good by the time the 280Z came out. Are you having problems with your wipers? The only maintainence I ever did on my78's wipers was to clean a lube everything when I bought it and they were trouble free for the 12+ years I owned that car after that.

Edited May 27, 201113 yr by sblake01

Mine are slow in general, and the linkage is very loose or sloppy which makes things worse (see other topic on rebuilding linkage.)

A stronger motor on bad linkage will only do more damage to the linkage.

Replace the linkage or rebuild it to a tighter state, Lube the pivots, joints and bushings, THEN replace the motor if you still have a problem.

I told Hogie to do the same to his linkage.

Dave

Its a Classic prone to rust! Don't drive it in the rain.

I couldn't resist.

Bonzi Lon

I don't drive mine in the rain because some meathead shaved the drip rails and my knees get wet. I already cleaned and lubed my wiper linkage before switching to the honda motor.

My stock motor actually worked reasonably well, but faster is always better for wipers.