I decided to upgrade to having intermittent wipers in my 79 F150. I ordered up the module and switch from E-bay that supposedly is plug and play. The connections connected, but the result was: no intermittent wiper, one swipe and one swipe only on slow speed, and only high speed worked properly.

I surmised that there must have been a defect in the used module. I just tried again, and again things plug in, but don't work. This time I only have high speed wipers.

Am I missing something here?

 

Are you sure you got the correct w/s wiper delay switch? And the correct plug and play box? 73-79 box (big pic) is plug and play, 80's (little pic) and up there are a few re-wire requirements I do believe.

Here is some ND knowledge and #'s: Two*different*types of windshield wipers, two*different*wiper switches.Two speed wiper switches have a*low*& high speed.
Intermittent (delay) wipers were optional on 1973/79 F100/350's and 1978/79 Bronco's. Intermittent is*not*another name for low speed!
DOOZ-17A553-A*.. Two Speed Wiper Switch-Not*used with intermittent wipers (Motorcraft*SW-896) / Marked:*D0OB-17A553-A*or*D*/*Obsolete
1973/79 F100/350 / 1978/79 Bronco // 1970/71 Fairlane/Torino/Montego / 1970/72 Maverick/Comet.
SUSANVILLE FORD in Susanville CA*= 530-257-2137.
NOS ONLY in San Jose CA *= 800-667-6659.
WESLEY OBSOLETE PARTS in Liberty KY*= 606-787-5293.
GREEN SALES CO. in Cincinnati OH*= 800-543-4959.
D1OZ-17A553-A*.. Two Speed Wiper Switch-Used*with*intermittent wipers (Motorcraft*SW-1010) / Marked:*D1OB-17A553-AA*/*Obsolete
1973/79 F100/350 / 1978/79 Bronco // 1971 Fairlane/Torino/Montego.
NOS ONLY
BURNS FORD in Burns OR*= 541-573-7278.
WESLEY OBSOLETE PARTS
GREEN SALES CO.
And D1OZ-17A553-A*.. Two Speed Wiper Switch-Used with intermittent wipers (Motorcraft*SW-1010) / Marked: D1OB-17A553-AA / Obsolete
DON'S TRUCK SALES in Fairbank IA= 319-365-2751.
MCDONALD OBSOLETE PARTS CO. in Rockport IN= 812-359-4965.
WESLEY OBSOLETE PARTS in Liberty KY= 606-787-5293.
GREEN SALES CO. in Cincinnati OH= 800-543-4959.
CARPENTER*NOS OBSOLETE*PARTS in Concord NC*= 800-476-9653.
There are TWO different intermittent wiper governors. 1973/77 is one type, 1978/79 is another.
D3TZ-17C476-A*(replaced D1ZZ-17C476-A) Intermittent Wiper Governor / Obsolete

 

I got a used one last year and installed it in one of the work trucks, same thing. BUT THEN I hit the black module that (I assume) has some type of relay in it, and it started working. It would work a few times, as in: turn on intermittent and it works, turn off, turn on low-fine, turn on high fine, turn on intermittent fine, let a few swipes go by, off, int on, works, off, on again and works, turn off. And then drive around a few days, turn on in rain, works. Drive some where else, works. Drive somewhere else, DOESN'T work. And the pattern repeated, so we put a standard high/low switch back in. BUT everytime I would hit the black box it would work again, maybe they just get sticky when sitting for a while....? END RESULT: Defect is is over-comable for short periods if you like "Personality" in a vehicle (switch says: But I don't feel like doing what you want right now, I'm just going to rest instead...)

 

Had the same problem with mine too. I used a small knife to clean all the male pins. I also discovered one of the connectors pulled loose every time I
installed the darn thing. After that it worked great. Don,t forget to turn the **** backward to use the intermittent feature.

 

Some of these boxes have solder joints on the circuit board crack causing all kinds of weird problems. If you take the board out of the black box and look on the bottom with a magnifying glass you may be able to see the cracks. Just take a soldering iron and touch it to each joint long enough to see the solder melt and it'll restore the connection. I've seen two boxes like that and one where the solder joint was so bad a capacitor fell off and was rattling around! All three work fine now.

 

Also, the switch must be grounded for the delay to work properly. It grounds through the dash once it's installed. Replacement switches have a separate ground pigtail because the same switch is used on the later 80's models that had "plastic" dashes.

 

https://www.ford-trucks.com/forums/1...l#post15809003

 

That link has a great answer and the follow on one, "post #14" in the following link is great on too, with pics.

 

I have taken a closer look at two module boxes I have. I don't have quick access to a soldering iron right now, but I looked at the circuit board in both. One of them has loose joints where the heat sink attaches.

Both seem to be late 80s part numbers. One is E7TF the other is E9TF. I have 3 switches that fit the wiring harness and have two clicks to the right and a rheostat to the left. Two are Motorcraft withe E7 part numbers and one looks like a repro that looks the same as the other two.

 

I took the box that had the loose heat sink and soldered it solid as well as touching up the other solder connections.

The result is that the box buzzes. I was grounding the switch.

Is there a wiring difference between the 80s boxes and the 70s even though the connectors are compatible?