my car keeps burning the 30a window motor fuse.. every time i drive i burn one.. it will roll the windows up and down for about 1 minute, and then burn out and stop working

i took the door panel off and looked for a short or anything that would cause this, but found nothing.. all the other fuses are working and unburned.. what the f*ck?

i pretty much have to put a new fuse in every time i drive my car. help

 

sounds like a short somewhere. if it were the motor or something constantly shorting, you would pop the fuse immediately. start chasing wires

 

remove the winder switches, replace fuse, look up the wiring diagram so you know how much of the system you look off the "could be list". check the remaining. rinse repeat.

 

You have a short somewhere. Super ultra BASIC electrical diag 101
1. Get a wire diagram
2. Get a volt meter
3. Trace your grounds on the wire diagram
4. Connect one volt meter probe to a 12v source and use the other probe to check for an available ground at ur ground points on the circuit. A good ground will show you source voltage, anything significantly less implies high resistance/ bad ground.
In all honesty you have a bad ground somewhere, if you don't show to have a ground after checking, trace your ground wire to its grounding source, look for kinks in the wire or corrosion , which would give it high resistance causing a bad ground and blowing your fuse.
You can also check the continuity of your ground wire, but I don't know what your skill level is with electrical diagnosis. You can PM if you have any other questions. Good luck

 

I am horrible at electrical stuff.. I still can not find out wha is going on

 

I don't think he has a short, I'd suspect that misaligned tracks, dirty guides and carboned switch contacts are forcing the motor to pull too many amps.

 

My first guess too. An intermittent short would be inconsistent and any kind of actual 'short' would immediately pop the fuse. My inclination would be to get an induction-ammeter-clamp and clip it around the power wire near the motor, should tell you how many amps the motor is pulling. Then disconnect the motor itself from the window mechanism and again test the amperage draw. That will tell you where the problem is, the motor or the mechanism.

And Hollow, a bad ground means increased resistance in the circuit. Which means less current flow, not more. A bad ground would cause the motor to not work all the time, or to perform poorly.

 

Yes I said high resistance which mean less voltage and higher amperage, never said more current flow. And when that amperage exceeds the fuse, it blows so he doesnt melt wires. Honestly, he needs a wire diagram of the circuit and needs to bust out a multi meter. Do a voltage drop on your window switch to see what the load is while the switch is in operation. Do a voltage drop on the window motor as well. Also he may have an intermittent bad ground, with as old as these cars are, he may have several issues.

If you lived near Dallas, I'd be more than willing to help you diagnose this at my shop.

 

Tachikoma, If said motor performed poorly, it would be moving slower than normal. If you recall Aaron Cake's E-fan articles, an electric motor has its greatest current draw at 0 RPM. Poor connections are why I was having issues with the starter in my 20B FC build. It would crank slowly, then trip the 150A breaker in 10 seconds. The solution was to go through the car, check every connection and resolder cables where needed.

Poor or corroded connections, either positive or ground, would increase the current draw in this manner as well. This is what Ohm's Law is about: V=IR
Voltage = Current (in amps) x Resistance (in ohms)

Corrosion on a connection increases the resistance, so the motor draws more power to compensate and it blows the fuse once it draws more than 30 amps every time. Read the following article about Ohm's Law and it will make more sense: http://www.aaroncake.net/rx-7/grounding.htm

What I would do is check & clean the window switches first, then the motor grounds. The switches carry the whole load of the motors' current draw and carbon up from the excessive arcing pretty badly over the years. The proper fix is to add two relays and some new wiring. This puts the load on a cheap replaceable relay that's made to handle 40 amps instead of the much more expensive window switches.

While you have the door panel off, it would be a good idea to test the motor alone. The way it works is that if you apply 12v on one side and ground on the other, it runs one way. Reverse the connections and it runs the opposite way. This is essentially what the window switches do and is called a DPDT Reversing switch in electrical terms. That is short for Double Pull Double throw. Easiest way to explain it is that it has two inputs (the "Pulls" and for each one of those inputs, it has two outputs (the "Throws"). Six terminals total. Reversing switches have two of the outputs connected together, but I cannot recall exactly how. Google will have the answer though.

 

Do the fuses blow if the window is not used? The fuse also powers the AAS actuators.

 

yeah the fuse will just randomly blow.. i finally found a bit of the aas wire exposed last night, and taped it up.. hopefully it was that simple

 

My apologies for my incorrect pontification.

 

I'm having a very similar problem with my windshield wipers/fuse.

They work w/they key to acc, but they move slowly on all speeds. Not the same speed, but rather a fraction (2/3 lets say) of the speed they should be moving. The wiper switch works on all speeds, and I even swapped in another switch, and got the same results.

If the car is on and I try to use the writers they will work for a while but eventually the fuse will blow, this apparently happens even if the wipers are not used since the last fuse was installed.

The only recent changes (they used to operate at full speed and would only blow a fuse occasionally) is that I painted my engine bay and wiper motor.

 

Check your linkages, sharingan.

 

did this fix the problem?

If not:
I would look for mechanical resistance, ie clean and lubricate the dirty tracks.
I would look for short.
I would clean the contacts on the switch.
I would install the relay modification.

If this were all done and the problem still happens, install a 30 amp self-resetting relay for a time to see if it solves the problem.

 

Your assessment of higher electrical resistance causing higher amp draw in the circuit may be correct but-

The definition of amperage is current.

Higher amperage *is* higher current flow.

 

Check them for what exactly? I cleaned out that whole cowl area and shot some paint on the rusty areas. Perhaps I should spray the linkage w/ wd40 or lithium grease?

 

I don't know why you'd spray a solvent on the linkage but lithium grease might not hurt.
The point here is to ensure the linkages aren't binding and overworking the wiper motor.