Slow and labored power windows

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FireTruck1984

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I think you are just seeing the grounds and switched/battery power. They don't care at "idle/no used" but the 2 left relays are for up/down driver side and the 2 right relays are for up/down passenger side. I just curious as to why the diodes were drawn on the picture. I see that its for the pass. side switch, just no sure as to why one wouldn't put them on the pass. switch side as well when operating the pass. window with the driver switch. confused.
Thanks for the great info !
 

FireTruck1984

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Not sure where I took this from, so I can't give credit to the original author.

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This is very helpful ! Thanks
 

FireTruck1984

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Check your grounds, check your battery resting voltage, and check your alternator output at the alternator and at the battery if this issue is happening with the vehicle running. If you’re missing a ground or one’s making poor contact, this can happen. You can also lubricate the run channels with silicone spray or dry lube.
Thanks, I’ll check those areas
 

FireTruck1984

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You should really go to a "switched power" source rather than the battery. It will lead to power drains on the battery.
OK, I’m a novice with electrical components but I’ll try to figure it out
 

FireTruck1984

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Agree with the relay modification. It makes a world of difference.
A lot of suggestions for this fix, I will try it . Thank you !
 

Doppleganger

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You can run the relay straight to the battery but it still wont work until the key is on. Common upgrade for headlamps that way too.

I pulled the power window sub-harness from a Benz sedan - complete with Bosch relays to use for mine. Just have to solder the corresponding switch wires to the harness. IIRC cost me a whopping $10. lol
 

Snoots

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One thing to check is if you might have thick glass in thin glass weather stripping. I'm not sure when the change over to thin glass was (early 80's I think). With them mismatched it will cause binding. with these trucks being as old as they are its not out of the realm of possibilities that the glass was swapped or replaced.

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1977 I believe. When power windows became available.
 

FireTruck1984

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You can run the relay straight to the battery but it still wont work until the key is on. Common upgrade for headlamps that way too.

I pulled the power window sub-harness from a Benz sedan - complete with Bosch relays to use for mine. Just have to solder the corresponding switch wires to the harness. IIRC cost me a whopping $10. lol
Great idea! Thanks
 

Chaz

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I just recently did the lmc truck relay upgrade on my suburban. Ended up replacing drivers side door switch....4 switches in one assembly. And the pigtail... Still had problems until i realized the connectors that go to the motor were bad....replaced 2 connectors at front two motors....and now my windows work great.....lots of power and they are faster than my wifes 2003 suburban windows....if your motors are original than u might want to replace them i had two motors on the rear door....one outta parts truck door.....and they were super slow....replaced the motor with new lmc truck motor....60 bucks....and works great now.....
 

Chaz

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I like the lmc relay kit because its super easy install with good directions.....i dont think i could build the relay kit myself.....i hate doin electrical......its a 40 dollar kit for 2 doors....comes with everything pre made.....i didnt even solder any wires just used the crimper and butt connectors and elec tape.....just didnt have time to solder all those wires......works great now....
 

FireTruck1984

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I just recently did the lmc truck relay upgrade on my suburban. Ended up replacing drivers side door switch....4 switches in one assembly. And the pigtail... Still had problems until i realized the connectors that go to the motor were bad....replaced 2 connectors at front two motors....and now my windows work great.....lots of power and they are faster than my wifes 2003 suburban windows....if your motors are original than u might want to replace them i had two motors on the rear door....one outta parts truck door.....and they were super slow....replaced the motor with new lmc truck motor....60 bucks....and works great now.....
I replaced the motors and regulators.. it seems like a power issue
 

C10MixMaster

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Not sure where I took this from, so I can't give credit to the original author.

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This shows for 73-87 which is not accurate. 73-76 no power windows 77-81 grounded through the motors and used a different motor switches and wiring. The relay upgrade shown should work for 82 and up.


The windows in my 77 are slow as molasses I usually only use them with the engine running.
 

gmachinz

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That diagram posted up was from a Corvette forum many years ago and its misleading at best trying to apply that to 77-81 trucks and is 100% NOT accurate for 1982-up trucks.
 

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