[chevymaher]

I have just completed the impossible corbonite maneuver.Whoever was involved in this thread they are Da Man.I was ask to go to the store.Got in the van.Humm window went up an inch and stopped.That's new.Well on the way to the store in the cold' it went up a inch at a time every couple minutes.Well I am stressed my baby is ill.Then I had a passing thought.

I remembered this thread and started studyin up Jethro Bodin style.
Well after grumbling about the door panels being impossible to get off without hurting them, I went for it.Only thing I did different was took out the stator assembly to get the brushes back on.Held the stator assembly with a pick while I fought the magnetic forces getting it back into the magnets.
I used Mass air flow cleaner on all the connections and brushes.Soldered that breaker joint.And greased the inside of the motor and the moving parts of the window track.Got it together and I was singing hallelujah.Works like brand new.Saved myself a heap of dough on a window motor Reckonin while I transpired. :character-willie:

 

[cookiemonster59]

[/1st let me establish my credentials: I was a 20 yr. Navy Electronics Technician. After retiring fm. the service, I continued applying my electronics skills as an Electronics/Computer Technician for Radio Shack, Tracor, Inc., & Bendix Field Engineering, etc. Even though I am 'officially' retired (again), I still dabble in doing washer & dryer repairs, electrical wiring repairs & installation, etc.

That said, I think what you are calling a 'resistor' in the window motor, appears to be more like a 'thermal disconnect', which is a 'Bi-Thermal' piece of metal. What happens here is when the motor draws too much current, this piece of metal heats up, bends, and breaks the contact, stopping all voltage/current flow, thus stopping the motor. When it cools down again, it remakes the contact, allowing voltage/current to flow again, until it overheats again. By soldering the end that opens when it heats up, you keep voltage/current flowing @ all times. This will work, until the motor overheats for once & for all, a wire or contact 'melts', etc.

Now that I understand this, it makes more sense to me, as I've noticed that my power windows tend to 'stall' more in warmer months, or on hot days, than in colder months/days.] :2:

 

[chevymaher]

Yes it was a bi-metal strip thermal disconnect.Corroded high resistance across the connection.Brushes were full of burnt grease also causing bad contact,due to brushes not extending correctly.In turn the motor was drawing to much current due to the resistance causing it to open almost immediately.As long as the window moves overheating is not an issue.If the window locks/hangs up then you have a overheating issue.Fix the window track and don't lay on the button.Brushes next in line to wear out now.They were about half worn.

 

[RECox286]

I believe I suggested that a manual reset c/b be wired into the line when doing this particular "rebuild" since what it does is to

shunt the thermal switch that is in the circuit. The T/S probably was put there in the first place for a good reason, No ?

Bob

 

[chevymaher]

I was doing follow up homework on the window bi-metal strip over-ride in this thread.Due to concerns of burning things up.On the fuse panel with all the other fuses, there is a breaker for the electric windows.So it is still protected.Blow that one they both go out.

 

[RECox286]

Hey CM,

You have to take into account that the auto reset c/b that comes with the truck is sized so that both windows will work at the

same time. When one of the window thermal switches opens, and since the c/b has not tripped, the other window will still work.

That is why I advocated a manual reset c/b sized to trip at slightly more than what the T/S is set for. (If that makes any sense.)

Bob

 

[chevymaher]

Hey CM,

You have to take into account that the auto reset c/b that comes with the truck is sized so that both windows will work at the

same time. When one of the window thermal switches opens, and since the c/b has not tripped, the other window will still work.

That is why I advocated a manual reset c/b sized to trip at slightly more than what the T/S is set for. (If that makes any sense.)

Bob

Yes I considering all possibilities.I am considering the breaker in the motor itself is to protect the windings which are more fragile than the van wiring.Seeing as the motor is not serviceable unless this procedure is done,that is a mute point.The wiring is protected by the breaker.That is my theory at this point.I wish my 90 van was still around I would go directly short the wires and hit the button see what really going on.Yes a in line fuse would be a good idea.What value would it be? With out having a guinea pig like my old 90 would have been.A guess is as usless as nothing if your wrong. The original poster never had a problem he messaged me.I have not so far.So I guess we the guinea pigs.Really if I had the value I needed I more than willing to put it in.I still working on it looking for the bi-metal switch value.I hear ya and I ain't thrown in the towel just yet.

 

[RECox286]

Well, the P/W breaker, fuse, what ever is rated at 30A. So if you cut that in half, less the safety, which keeps the darned thing working

and not tripping, I figgure that it would be safe to, say, use a c/b rated at 1/2 the 30A plus maybe 5A less than that, or 10A .

Instead of shunting the two brass pieces with solder, solder a 10A manual reset c/b in paralell with the thermal switch and run the

wiring to a convenient location. With the motor in the circuit, and hooked up to the load (window) see if a 10A c/b trips out.

I'll bet it won't unless the motor shorts and fries, in which case the lower value c/b will be the protector. Of course it is just as

easy to replace the motor, because JY's are full of them. Even retail, they aren't that expensive, and they don't go bump in the

night every 2 weeks.

Bob

 

[Rey]

For the record, I'd like to say that the device being disabled here is most certianly not a bi-metallic strip. It may be difficult to see from the pictures, but the two bars are made from solid copper and are much too thick to have any mechanical action to them. It is also worth noting that during my initial investigation into what the fck was wrong with the goddamn thing that I applied heat to the joint with a soldering iron while measuring the resistance, and saw a steady increase rather than a sudden open circuit.

It is my opinion that this device was originally intended to only be activated in the event of a jammed motor (for example, the window is already all the way up or down), where the short circuit current would be sufficient to heat up the junction, increasing the resistance until it was so high that no more useful current could flow. I beleive that the failure lies within whatever compound is used between the two plates to create the thermo-resistor action. Either with age or use, the joint breaks down and becomes more sensitive, raising the resistance at ambient temperature. These few ohms of resistance are enough to generate heat during normal use, creating a positive feedback loop until, again, the resistance is so high that no useful amount of current can flow.

I hope this makes sense. :shrug:

 

[kinggrimwood]

This saved me $42. And it was super easy to do. Thanks a bunch.

 

[Sailing_Faith]

Great tip, will save in the memory bank.

FWIW, I had a weird failure today. Opened up the port side door to fix what I thought was a bad tooth on the regulator or motor (window would raise and lower part way then stop moving and make a loud clicking sound).

On disassembly, I noticed the rivets holding the motor had been removed and replaced with screws (motor had been replaced before)...

The problem was in the motor assembly transmission... not in the regulator at all. I will save this one, since it has a good motor I may be able to use it to rebuild what ever one fails next time.

Posting just to possibly prevent someone else from trying to buy a regulator if they had a similar problem in the future.

 

[cookiemonster59]

This was a very interesting and informative post. As a 20 yr Navy Electronics/Radar Technician, let me add my '2 cents' :2: about tolerances, figuring out what size fuses, ckt. brkrs., resistors, etc. to use. In school I was always taught that engineers use a 35% 'overage' factor when computing electrical 'safety' ratings. For instance, if a ckt. brkr. is rated for 20 amps, it will probably handle 23-25 amps momentarily w/o 'tripping', and the interior parts will be designed to handle 30 amps without substaining severe damage, but the 'trip' mechanism 'trips' @ 20 amps, of course. Of course, when I went in the Navy, we didn't have any DVOM's, we only have VOM's!! Simpson 260's to be exact!! My friend down @ KDT Electrical Contractors has one sitting on his counter. They were designed to handle a drop of 5' & still stay accurate. In some cases, an analog VOM is more accurate than a DVOM, especially when looking for 'average' voltages, because the needle doesn't react as fast as that 'chip' does. Also, true amperage readings only come when your meter is 'in series' with your circuit, not when it's 'in parallel'!! Just saying :wave:

 

[Sailing_Faith]

Looks like the P/W fuse is rated for 30a. Fairly heavy ! This must be the reason for the thermal reset protection in each motor. .....

Bob

I suspect it had to be that large, in the case that someone held down both switches at the same time so as to roll down both windows at once.

 

[chevymaher]

Seems reasonable on the ratings. Same things my brother an electrical engineer tells me.

But since we here again. I will give the hillbilly weather out the window report on mine.

Since feb we have discerned 2 things.

1 window still works like new.
2 Van hasn't caught fire yet.

 

[bparanoid]

Many thanks to the OP for this tip. I fixed my passenger side motor that was at a point that it would barely move an inch and it all went so well that I decided to do the driver side as it was starting to show sign of fatigue. Also want to thank Detroit_Dave for the twist tie tip..it worked like a charm.

 

[cowboydan]

this section proved usefull, being able to see what everything lookes like before hand means you can get through the job in record time. a plus for guys like me with little free time.

 

[A Random Bush]

Great Tutorial! I'm going to go do this right now on my '93 astro
One question though...how do I get this damn thing off?

 

[chevymaher]

Great Tutorial! I'm going to go do this right now on my '93 astro
One question though...how do I get this damn thing off?

What off? the motor.

 

[A Random Bush]

Great Tutorial! I'm going to go do this right now on my '93 astro
One question though...how do I get this damn thing off?

What off? the motor.

precisely. (Excuse me I'm a newbie)

 

[chevymaher]

Got to put a piece of wood in there to hold the window up.
So it don't fall and possibly break, or slam your hand in there when your unawares.
Drill the pop rivets out. After you get in so far they spin.
Got to hold the drill bit at a 45 degree angle or so and let it chew the end off till it comes off.
I used a nut and bolt to replace it. Makes it simpler in the future to work on.