Weird Power Seat Issues

When taking the seats out of my wife's '94 Mustang, I found that the seat motors didn't function. That made things very enjoyable, let me tell you.

While it was out, before reassembling the seats, I went through to test and see what was wrong. I tested voltage at the plug coming out of the floor, 12V. I tested voltage going into the motor plug, 12v there too, or -12v, if I tried to go the opposite direction on the switch. All as was expected. Felt the motor while actuating and no sounds, not even a feeling of a kick. Okay, bad motors.

Really? I thought - two at the same time? That seems pretty unlikely. But I ordered a set of replacement motors from Two Guys One Garage, and just finished getting them all installed. Got them wired back in. SAME ISSUE. They don't even try to run - no spinning, and I've got 12v all the way up to the motor with the switch actuated.

I also got a hammer and gave the seat slides a couple of firm smacks while actuating the switch, in case it was stuck and still nothing.

I'm out of ideas, anyone else have a theory?

edit:
I also want to add, I had disconnected the motors originally and ran them without any load on them to see if it was a bad motor or if the seats were jammed, and the motor did not spin while unloaded, so it doesn't seem to be jammed either.

90sickfox said:

Do you have ground at the switches ?

Sometimes you can have 12v to something but if the ground isn't working the motor won't work.

Click to expand...

I tested from one side of the plug to the other, so there was definitely a path to ground somewhere.

I just brought the seat base inside and hooked it up to my 12V power supply - same issue if I hooked it up the way the car battery would be... it would try to pull about .3A according to the readout on my power supply...

But if I connected directly to the motor (a bit at a time) then amps would jump to about 5A and the seat moved front to back... up down is still stuck, but it definitely tries now.

I ordered a new switch - I'm hoping it's just corrosion inside the switch contacts that's keeping enough amps from going through, but there's no way to get into the switch far enough to clean it up by hand. The replacement switch is only $70 on eBay, so it's not worth fighting with it too much more.