Sloooowwwww rear window...help, please?

[Wishmeluck]

84 Bronco....Rear window goes up and down painfully slow and stops partway in both directions. I can always pull/push it up/down the rest of they way by turning the t/g key.

It has a new motor, gears/tracks have been cleaned, lubed and it has new little glide thingys in the tracks too. The dash switch has been cleaned and the grounds behind the dash were all cleaned and renewed too.

Heres my conundrum:

- If I give it juice straight from a battery to the window motor on the window side of everything it shoots up and down great.

- If I hook wires up and give it juice so it works through t/g key ONLY the window will go up pretty well, but down is super slow and gets stuck about halfway.

- If I hook wires up and give it juice so it works the the dash switch ONLY the window goes up halfway and gets stuck, and goes down painfully slow.

I tested each scenario and get a full 12v when the switches are flipped to wherever power needs to go, and just to make double sure I even ran a dedicated 12v wire to the connectors and tried that too.

Since I was getting 12v everywhere, I thought maybe it was poor grounds. So, I also threaded the ground ***** hole in the drivers tail light area for a dedicated ground close by. One switch at a time nothing changed no matter the power/ground source combination.

Im trying to keep it as stock as possible and really dont want to admit that maybe after 40 years maybe the switches are just getting worn. Anyone have any suggestions I may have missed or overlooked aside from the switches themselves?

 

[johnnyreb]

84 Bronco....Rear window goes up and down painfully slow and stops partway in both directions. I can always pull/push it up/down the rest of they way by turning the t/g key.

It has a new motor, gears/tracks have been cleaned, lubed and it has new little glide thingys in the tracks too. The dash switch has been cleaned and the grounds behind the dash were all cleaned and renewed too.

Heres my conundrum:

- If I give it juice straight from a battery to the window motor on the window side of everything it shoots up and down great.

- If I hook wires up and give it juice so it works through t/g key ONLY the window will go up pretty well, but down is super slow and gets stuck about halfway.

- If I hook wires up and give it juice so it works the the dash switch ONLY the window goes up halfway and gets stuck, and goes down painfully slow.

I tested each scenario and get a full 12v when the switches are flipped to wherever power needs to go, and just to make double sure I even ran a dedicated 12v wire to the connectors and tried that too.

Since I was getting 12v everywhere, I thought maybe it was poor grounds. So, I also threaded the ground ***** hole in the drivers tail light area for a dedicated ground close by. One switch at a time nothing changed no matter the power/ground source combination.

Im trying to keep it as stock as possible and really dont want to admit that maybe after 40 years maybe the switches are just getting worn. Anyone have any suggestions I may have missed or overlooked aside from the switches themselves?

 

[johnnyreb]

Have you looked at the wires good? Look for blue color. Like maybe they got hot and looseing their continuity. Another thing that could cause it is --check the hot wire on the starter----if its loose. I found out the other day on mine-- When your dealing with wireing---it can get aggervated. Good look. Check the motor out good too. You can get BAD NEW PARTS. I went through 5 new starters in one day--from the parts store.

 

[lynchsg]

LMC Truck sells new OEM style dash switches. Check the condition of the plug going to the dash switch and it's wires for overheating.
In the tailgate key switch, clean the contacting surfaces with emery strip abrasive cloth that get dirty or corroded. Also check the switch wiring connections for corrosion etc.
There are a couple of in line permissive tailgate switches that are part of the circuit. I by-passed mine because of problems with them.

 

[chrlsful]

rigs this old I all ways ck GROUNDS.
Like any thing else, start @ 1 end (the
v e r y begining) and end @ window. Test
lght 4 continuity, multi meter for power level ?
Test either side of switches. Everything . . .

 

[L\Bronco]

84 Bronco....Rear window goes up and down painfully slow and stops partway in both directions. I can always pull/push it up/down the rest of they way by turning the t/g key.

It has a new motor, gears/tracks have been cleaned, lubed and it has new little glide thingys in the tracks too. The dash switch has been cleaned and the grounds behind the dash were all cleaned and renewed too.

Heres my conundrum:

- If I give it juice straight from a battery to the window motor on the window side of everything it shoots up and down great.

- If I hook wires up and give it juice so it works through t/g key ONLY the window will go up pretty well, but down is super slow and gets stuck about halfway.

- If I hook wires up and give it juice so it works the the dash switch ONLY the window goes up halfway and gets stuck, and goes down painfully slow.

I tested each scenario and get a full 12v when the switches are flipped to wherever power needs to go, and just to make double sure I even ran a dedicated 12v wire to the connectors and tried that too.

Since I was getting 12v everywhere, I thought maybe it was poor grounds. So, I also threaded the ground ***** hole in the drivers tail light area for a dedicated ground close by. One switch at a time nothing changed no matter the power/ground source combination.

Im trying to keep it as stock as possible and really dont want to admit that maybe after 40 years maybe the switches are just getting worn. Anyone have any suggestions I may have missed or overlooked aside from the switches themselves?

Hey wishmeluck!
Nothing more frustrating than electrical faults.
Sounds like 2 issues.
1st you have circuit resistance somewhere, second a window track adjustment issue.
Voltage loss will slow it down and drag will raise the current flow aggravating the resistance issue.
Start with the resistance first.
Hook everything up like it should be, factory everything, then measure the voltage across the motor while its running. (Both meter leads at the 2wire plug at the motor, you will need help.) Activate it from the dash switch.
Watch the voltage when it slows or stalls.
If its less than battery by more than a volt (when the symptom is there) you have too much loss.
Then measure from the positive wire at the motor to the battery positive post and redo the test. (Run it till it drags)
Repeat for the ground side.
If you find a big loss on either side, keep testing that side while moving your lead to connectors along your circuit, always moving toward the battery. Never take the lead off of the battery post on the side you are testing. (Positive to positive, or negative to negative.) only move the lead thats in the harness and make your way to the battery post.
Its called voltage loss testing and if done correctly, it never misses.
Hope that helps.
Good luck.
cheers

 

[Tiha]

Did 84 have the safety switch?

That was a huge source of resistance and slow window movement.

But ditto on testing. You have a bad wire or ground somewhere. Key switches wear out too.

 

[goodO1boydws]

I'm with L/Bronco.
If, as you wrote, the motor operates the window FINE-both up and down when you are supplying battery power to the window motor directly, that pretty much eliminates track alignment/adjustment as being much of an issue, but every little bit of lost efficiency hurts. My personal guess is that its liable to be losing a little bit of voltage along every section of the circuit, (old wires and switches, weak connections, marginal grounds) and its a cumulative voltage drop rather than coming from a single culprit. Do you happen to be where much salt is being used on the roads? That is a very common cause for gradually developing poor connections on older vehicles if they are driven much or not. The salt works its way in and never gets completely out, causing progressive oxidation/corrosion. This sort of thing often shows up first with exterior lighting circuits as their wires, connectors, and sockets are more exposed.

 

[Wishmeluck]

I did some more research and I think its actually the window motor itself. I went to a local pick and pull and pulled a couple of other key switches, wired them up, and got the same results, fast up/slow down. I thought no way its the same with all three switches, its gotta be wiring. I think my little battery is running a little low from all the up/down ive been doing with the window and I started to notice the window was now going slow all the way back at the motor. Its also not the original window motor..doesnt even look/fit like the original. I mean, it goes up and down but only two of the holes line up and it looks like driver/passenger door window motor. Gonna get that out and get the right one in first. I figure if an aftermarket heater blower motor cant warm up the cab but an original motorcraft can, maybe the rear window motor is the same and cheap china stuff just isnt gonna cut it. Thank you everyone for all your suggestions and will post up results when I get it swapped...

 

[Tiha]

Yeah that doesn't like the correct motor. I hope that fixes it.

Hooking directly to the motor for testing is great but it can be deceiving because it is able to send a lot more current to the motor and does not replicate your actual battery voltage or line loss.

 

[Wishmeluck]

It was 100% the motor. I didn't want to wait a week for delivery so I pulled a window motor from a 92' f150 (passenger side is a direct fit), tested it at the yard, and brought it home. Window goes up/down flawlessly with both switches. Picture is a side by side of the one available at parts stores they SAY will work (on the rhs), but I'm not sure how they can claim that when all the holes don't even all line up. Anyways, thanks again for all your help...on to body mounts!! (When it stops raining).

 

[lynchsg]

Only a slight motor winding size difference, too!

 

[Tiha]

Great visual reference, Thank you for the follow up.