Installed intermittent wipers this weekend...

[Guest Anonymous]

Since my car came before the mid-'71 model change, it didn't have the black relay also used on 320s that would have made the addition easier. Instead, I used a JC Whitney delay relay mounted on one of the underdash-board screws. A three-speed dash-mount heater blower switch replaced the two-speed wiper switch (early cars had all wiper functions except wash controlled by the lower-right binnacle knob).

The trick is that the wiper system feeds power to the motor through one wire on high but two wires on low, and both wires have to be connected to get the wipers to park properly. The original switch had multiple contacts to achieve this. I used an SPDT relay to achieve the same function.

The wiring diagram I used is below, prepared with the suggestions of a couple of people. Works slick, and with the exception of the unobtrusive under-dash box (which lets me adjust the delay from about 2 seconds to a ridiculous 20 seconds), everything looks factory.

-Dave

Colorado '71

[Guest Anonymous]

(nt)

[Guest Anonymous]

control? And what function does the STDP relay serve? I did a similar setup to yours but with a Radio Shack controller and didn't use a relay...

Mike

[Guest Anonymous]

The object is a diode, to keep juice from feeding back into the delay relay when the switch is set to low speed. I may not have needed it, but it's there and doesn't seem to hurt anything.

The SPDT relay serves to keep the "low" and "high" wires connected when the relay is depowered -- i.e., when the switch is set to off, intermittent or low speed. Both wires to the motor are receiving power at low speed, and the wires seemed to have to be connected at "off" to allow the motor to park properly. This arrangement is visible in the schematic of the switch in the diagram in the owner's manual.

At high speed, only one wire is needed (I think it was the black wire to the original switch). Thus, when the new switch is in the "high" position, the SPDT relay energizes and flips the contact over to run 12V through only the "high" wire.

It made sense to me, and, more importantly, it works. By the way, did you use a Bavaria three-speed wiper switch in your conversion? It may be internally similar to the original '02 wiper switch, eliminating the need for the relay in your setup. If, however, your car uses a blower switch as well, I may have overlooked a simpler wiring method.

-Dave

[Guest Anonymous]

had a stalk-mounted switch like the 72s and 73s. I have a Bav switch in my 73 for the intermittent position. I used a heater switch on the 69--no external diode or relay and it works OK but for one little quirk. If you switch the wipers off while they're actually moving in the delay mode, they immediately go to the high speed mode, so you have to turn them off when the wipers are at rest in the intermittent mode. Perhaps your relay and/or diode would eliminate that quirk. I just live with it.

Mike

[Guest Anonymous]

assembled to set the Agave car's wipers up this way, but hadn't started working on the actual wiring - one less thing that I have to puzzle out on my own!

[Guest Anonymous]

My only qualification is that the diode shown may not be necessary and may not be shown in the proper orientation (I'm not really an electronics guy). I say it might not be necessary beacuse I had it hooked up the wrong way at first and nothing strange happened, except for the intermittent function not working.

-Dave