[kansasgal]

I have a 1999 f150 the wipers won't go down when you shut them off they park straight We have replace the fuses, wiper motor, some multi switch, I think a relay switch. We have to take the fuse out and push then down. I don't know what it could be.

[TxGreaseMonkey]

I don't know exactly what the solution is. I would check the under dash fuse for the front wiper motor, under hood wiper speed relay, and under hood wiper park relay. Disconnect the negative battery cable, remove each relay, and clean the male connectors with abrasive cloth; afterwards, apply dielectric grease.

The alternative method, in the link below, is a fast and easy way to test all under hood and under dash fuses in 2 minutes:

https://www.askmehelpdesk.com/cars-t...tml#post252145

[CaptainRich]

The position of the ignition switch is very important to proper Generic Electronic Module/Central
Timer Module(GEM/CTM) operation. Often times, erratic or unexpected operation (or other poor connections) can be traced to problems on these GEM/CTM inputs.
They also make the schematic simple to follow so strategy based diagnostics is a cinch! NOT!
Here's the schematic anyway. Follow it carefully and it's not too bad:



The following is a brief description of five ignition switch positions:
When the ignition switch is in the RUN position, battery voltage should be present at the GEM/CTM RUN and RUN/ACC input terminals.
When the ignition switch is in the ACC position, battery voltage should be present at the GEM/CTM RUN/ACC input terminal only.
When the ignition switch is in the START position, battery voltage should be present at the GEM/CTM start/clutch depressed input.
The GEM module does not have an OFF or LOCK switch state input so the GEM will assume the OFF or LOCK position when there are no RUN, ACC, or START signals present.
A poor connection at the wrong time can cause numerous and varied problems.

[lilpoppa]

Could be a problem with the wiper motor assemblys internal wiper position swith, have had a similar problem on a 02 f150 my soultion was getting a new wiper motor/drive unit from the salvage yard for $15, and throwing it on in the parking lot. But since you already replaced the motor assembly, try turning the wipers on then shut them off shut the ignition off, unboldt the motor assembly, push the wipers down and reinstall the motor, the output shaft on the new motor could have been clocked wrong when you originally installed it.