Hello out there ! This is a question that I hope that someone can help me.Well it rained this weekend here on the coast in oregon but whats new?.Anyhow I turned on my wipers and only had high speed and no low although there was at one time .My question is ,is it the switch or will I have to replace the wiper motor?. also where is the coil on a 90 F150 with the 300 six ,because sometime in the future I want to install a tach. Thanks for all your help. Hope to hear from anybody soon
sixshootr

 

Howdy and welcome!

Follow the center plug wire on the distributer and it leads right to the coil.

Do you have interval wipers if you turn the **** to the left?

Adrianspeeder

 

tachs are simple on the 300, when you buy a tach it tells you which wire on the coil to connect the tach, that is the hardest part of the install

 

thanks for the reply.And to your answer,yes if I turn the **** left I should have intermintent but I dont ,just high speed.And no low so hopefully it,s just the switch yes?????.Thanks for your help
sixshootr

 

I have the same exact problem on my truck. High works, but low and intermittent dont. For a while I could get "lo" and int. to work if I smacked the dash right above the heater controls. Now that doesnt work anymore..
I still need to find out whats causing it.

-Dave

 

Most likely the switch.

Adrianspeeder

 

If high works, you know the motor is working properly. The motor assembly itself is just that: A motor and the cam gear or whatever. The delay for all other speeds is controlled by a seperate relay.

Chances are the switch is bad. Does pushing it in cause the fluid pissers to come on, or are they not working either?

 

In my truck the fluid still sprays when you push the switch..
What would I have to replace to fix it? The switch itself, or is there a relay for it located somewhere else in truck? I havent looked at how its setup closely enough to know how everythings wired up down there yet...

-David

 

sixshootr:

I had the same problem on my 1990 F150 Supercab Lariat.

You probably have a defective wiper governor. It is a small black box that controlls the intermittent speed.
There is a little part in it that can become unsoldered off the circuit board due to vibrations.
You need to resolder it. That will probably solve the problem.
After having had to resolder that thing twice, I found a used working governor
at the junk yard for $30 (including the switch and harness).
The local Ford dealer charges $160 for the new wiper governor.

This is a common problem on the wiper governor on the 90's F150.
This has been discussed here often. See, e.g.,

https://www.f150online.com/forums/sh...wiper+governor