It happened to me this morning, the middle of a rainstorm... The dreaded 2 speed wiper switch failure. Nellie (My 1978 LTD II) is my daily driver at the moment, so I had
to come up with a fix to get me by while I track down a replacement. While
tracking down the switch pinouts I found several references to people
trying to use toggle switches without any luck, so I decided to share my
solution. This works, and in my opinion is much safer than trying to
hot wire the motor from under the hood, which it seems people have
tried.
That being said, I must state this disclaimer...
***I am not an electronics expert. I assume no responsibility or liability for any
damage to your vehicle or other property for attempting this repair.
This is a temporary fix, not a permanent repair. As always disconnect
your battery before working on the electrical system***
First
thing I want to show you is the pinout continuity test for the switch. I
have an entire Adobe file with wiring diagrams and testing procedures
for 77-82 Ford wiper systems if somebody wants to suggest a way to share
I would gladly do so.
Looking
at this the first thing I noticed that any time the wipers were on in
low or high the terminals A-G-H had continuity, or were connected
together. The only difference between speeds was which terminal C or E
was connected to D. I looked at the base of my separated switch.
I
noticed terminals A & H were always connected together with a 8 1/4
amp circuit breaker between the two terminals. when the switch was
rotated to the low position terminals C&D connected and G&H
connected. Turn the switch to high and D&E connected and G&H
stayed connected. I was ready to mark my switch socket and wire a
bypass.
I
discovered Molex .093 male pin crimp terminals fit the female terminals
in the Ford factory connecter. These are pretty common. I got mine from
a 9 pin molex connecter kit from Radio Shack part #2740229. Napa and
Car Quest should have them in their Weather Pack connector supplies. You
might be able to raid some from connecters at the junk yards, if you go
this route make sure the wire is at least 16ga. Here's a picture of the
pin terminal.
I
crimped the connecters on lengths of 16ga wire then soldered them. I
pushed one into Ford connecter on the vehicle. I then slid a length of
heat shrink tube over the wire and pin terminal until no metal was
exposed. I repeated that for the remaining leads. Sorry I don't have
pictures of that I ran out of light and the half of me hanging out from
under the dash was soaked. Here's a very basic circuit diagram I made in
MS Paint. I hope it makes sense.
The
way I am running it terminal A connects to an ATC (blade style) fuse
holder I have a 10 amp fuse in it now, but I am replacing it with an
8amp circuit breaker that fits the holder as soon as I receive it from
O'reilly Auto. The wire exiting from the fuse holder connects to two
wires, one plugs into terminal H, the other connects to one side of a
toggle switch. The wire from terminal G connects to the other side of
the toggle switch. That completes the power side of the wiring. The
speed control side is as simple as you want it to be. Make a jumper and
connect terminal C&D for low, or terminal D&E for high speed. I
included a example of how to wire a SPDT switch to change speeds on the
fly, if you have room to run a second switch. The only switch you have
to turn off is the power circuit, you will not have park function, but
at least you can use your wipers in an emergency while you're waiting on
that replacement switch. You could also take 12volts from the
terminal G side of your power toggle switch run it to a momentary on
push button switch and then to that terminal marked with a "W" and your washer pump will spray.
Please be careful, don't eliminate the circuit protection. Use a circuit breaker of some sorts, no bigger than a 10amp. Be safe!
Lee's 1978 LTD II
A project diary for my latest obsession. This is my fourth LTD II, and hopefully I finally build it into the car I always wanted. I am quite experienced with these vehicles, and will cover some issues I can't find solutions for on the internet.
Wednesday, March 11, 2015
Saturday, February 28, 2015
Love at first sight...
So I found this 1978 Ford LTD II S with 57,218 original miles. Yes, I am positive it's only 57k. It can be tricky on the older cars that have odometers that roll over at 99,999 miles. You can tell that most of the wear and tear on this particular car is from age and not mileage. The first time I saw this car it was being sold on consignment and the minimum price was $5,500. Well time changes everything and 3 years later I drove her away for $1,900 cash. This car is worth every penny, but it's worth noting that of the 4 LTD II's I've owned it's the first I have paid over a $1,000 for. That's inflation for you. LOL!
I have all the original paperwork including the build sheet, special order form, manuals, vehicle test report, and 30+ years of maintenance receipts
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