Rolled down window for drive-thru. 15 minutes later both switches/windows dead. When I press any button relay under dash buzzes from several seconds to constant. Metered switch, 12 volts going in driver’s side, 5 or 6 coming out. Ground wire shows continuity. Switch and relay are new. I’m officially lost but don’t want to pay $$$ at a shop if possible.

 

Welcome to the forum

The passenger side switch has its own 12v wire, does it work?
If not then most likely Safety Relay issue

There are two relays
One Touch Relay just for drivers window
Safety Relay powers both door switches

Both Relays are located in Relay Box 1 above gas pedal in cab, it has a cover over it and faces E-Brake pedal, take cove off, press button and see which relay is "buzzing"
Pull it and replace it

2002 diagram below

 

LtBlue power wire does have 12 volts. I pulled buzzing relay, replaced it. Also replaced switch for giggles. Pressed button, no change, still buzzing. Black ground wire shows good continuity.
Am only out $30 so far.

 

Does the passenger side window work using its switch or same buzz?

 

Buzzes also. This is why I can’t see the motor being bad as others have suggested.

 

No, for sure not window motor

Check fuse 12 in engine fuse box, for 12volts, well key off test battery voltage first then pull out fuse 12v and test its voltage needs to be EXACTLY what battery showed

Test battery voltage again but with key on, remember it
Then test either window switch's light blue/black wire for that exact voltage

With no Load voltages should match exactly, if lower then there is a bad or corroded connection somewhere
With a load, like a power window motor, you can lose 50% or more voltage thru a bad connection

Since you are hearing a reaction to the switch being pressed the "Load" is connecting to fuse 12 in engine bay
And since relay was swapped its not in the relay

 

Good point, will try. As said, I have 12v at bl/blk but when under load to motor only 6 coming out, but will recheck with meter as test probes are not the most reliable. I am confused abt one thing. The buzzing (replaced) relay was the one touch, which doesn’t affect passenger switch supposedly, yet it also buzzes. Could a bad safety relay be affecting the one touch relay and resulting buzz? I’m thinking a lit rag in the gas tank is the best fix.

 

No, the lit rag in gas tank will just add other issues, windows would still not work

Correct one-touch relay should not effect passenger side window switch and motor in any way
Pull it out
See if passenger window switch work

Now the passenger window switch and motor are grounded thru the Master switch, so it need to be plugged in

All power window systems work the same way, each switch has its own 12v wire but each switch is grounded via 2 wires from Master switch
Thats how the Master can control other windows

If you want to test the system start at the 2 wire connector for any motor, both wires on that connector should be GROUNDS if no button is pressed, so 0 ohms to ground and 0 ohms between the 2 wires since they are both grounded

If one wire is not a good ground then problem is usually in a switch

The one touch relay passes the GROUND to the driver side motor's red wire when button is not pressed, so relay must be plugged in to test that

Motors are activated when a button cuts one wires ground and gives it 12v, other wire is still a ground so motor activates
As per diagram both motor wires are grounded when buttons are "off"

You can take the one touch out of the system if it seems to be the problem
In the diagram, Master switch pin 4 a tan/blue wire is the drivers side window motor wire(same color wire in 6, so check that)
It is sent thru the relay and GEM then back to the Red motor wire

You could cut the tan/blue wire and the red motor wire, then use a jumper wire to connect them together, by passing the one touch system
But Last resort

Test the 2 motor wires FIRST, key off, both need to be good grounds with switch plugged in, if on drivers side then bad switch, new or not, usually
If passenger side then can be bad master switch or bad passenger switch

To effect both windows its 99% a master switch issue

 

Here’s where I am-fuse 12v bl/blk wire at switch 12v. However, the 12v is when I ground meter to chassis. If I use the black wire, which should be the same thing, I only get 10v. Under load, switch does only puts out 6v to motor. Also when I pull the buzzing (new one touch) relay passenger switch also dead. Guess it’s possible but not probable the safety relay is bad. Could the contacts at switch be dirty? Other than a wiring issue between relay(s) and switch, which would cost $$$ at a shop, I have no idea where else to go. Thought: could a bad passenger switch affect master switch?

 

The Ground for Master is behind the drivers side kick panel, either is it failing or the wire from there to the switch is failing, that's why Passenger side is effected, all windows/switches share that one ground wire, should be a bolt with several cab ground wires attached

Because drivers door is the one that opens and closes the most the wires that run thru that rubber boot are bent back and forth, A LOT, lol, so one can fail

 

Thanx for all your input. The first I checked was ground behind kick panel, was bolted tight, no sighted broken wire. Will run wire from switch to a reachable ground point. If works, then will engineer new wire thru boot and bolt. Hope Hope Hope.

 

Just test 12v wire at switch to the bolt and see if it reads full battery volts(meter's probe wires should be long enough for that), if so, but only 10v at the switch ground wire then yes a new wire would be needed

 

Final post thanks for all the help. Was ground. Ran separate wire from switch to a body ground. Success. Took a week and hours of research to go full circle. Never dawned on me a frayed ground will still read continuity but not complete the ground. Next issue is trying to push or pull a 16 ga non-rigid wire thru the door boot. Hoping I can find a grounding point just inside door, tho there can be prone to moisture. At least problem solved, just need to accomplish fix.

 

Home 18ga electrical wire works well as a "fish stick", its solid copper so holds its shape when pushed but will bend as needed going around things
Tape the 16ga stranded vehicle wire to it and pull it through

Metal Coat Hanger wire works as well but can be too stiff, have to pre-bend it to get around things
Bailing wire works but can be to bendy it you push to hard it just bends without moving through where you want it to go

 

Did end run. Drilled hole next to switch, put in #8 screw. Attached spade connector to wire and tightened & siliconed. I’m not standing on formality. With 400k miles and all original except for the normal maintenance needs and rebuilt engine, one or both shoes will drop big time at one point or another. Everything now is basically a means to an end.

 

Thank you Ron D .Answered a question I have had for a long time.