Parhelius

I have had slow power windows ever since I bought my Series II RX7
I have tried everything from aligning the windows, to replacing the window motor and servos, and a relube, and nothig fixed the problem.

So I then looked at the electrical side of it, and by putting a voltmeter straight onto the battery terminals, I registered 12.38 volts without the engine running. I then mounted another volt meter to where the voltmeter in the dash instrument display cluster is. And again, I got 12.37 volts. No difference basically.

I then used the power windows, and the inside voltmeter drop to 10.67 volts, but the voltmeter which was connected straight to the battery was registering at 12.29 volts.

So that means the battery can supply this current easily, but it wasn't getting to the window circuit at that voltage, only when you arent using the power windows.

So as a basic test, if you have slow power windows, which pretty much stop as they get raised, try this.

Raise your power windows (both of them at the same time) and while doing this, turn on the front driving lights, and the cabin ventilation fan to 4. If the windows slow down even more (or pretty much stop) then you have this problem, which can be fixed quite easily.

Run a length of 15-20 amp red cable from the positive battery terminal into the cabin, and to underneath the power window switches. Then you must cut the *black cable with blue stripe* on both of the power window switches, and connect the red cable to the switch side of the cut cable for both switches, and tape or heatshrink the other half of the cable you cut (which goes back under the carpet)

This will supply the windows with fresh current straight from the battery, instead of through all the cars electrical circuits (which are overloaded). And they should both together raise in under 5 seconds.

This fault is because of the cars internal wiring. Everything runs through a cable somewhere which cannot supply enough current, resulting in a voltage drop when you run a few accessories, and this can prevent the windows from working properly.

If you like to add lots of electrical bits to your car which draw significant current, run a cable straight from the battery to supply each component, or run a length of 8 gauge cable or something into the cabin, then split it from there to each appliance. Dont just add it onto the cars factory wiring, unless you add a relay.

This includes amplifiers, fuel pumps, tv screens, high power head units, exterior lights/fog lights etc etc.

Excuse the long post, I just needed to explain this fully :P

mwpayne

Good idea, 20 year old wiring and connectors do build up corrosion. I'd add a fuse to the supply wire.

yayarx7

I used to tear apart the window switches and clean the heck out of them every 6 months or so to combat some of hte voltage drop. Also clean up all the connetors you can reach with contact cleaner. If you do not want to run the wire that is....

RotorMotorDriver

iTrader: (1)

Yeah, Ive seen people just install relays for them too, but this seems so much more simple. Im going to try it on my 83 when I redo the electrical system rather than the relay method. No extra junk to mount somewhere .

~T.J.

Cloud

That is a horrible, horrible idea.

Pedestrian X

Could you explain why, im a noob to stuff like im jsut curious, thanks :]

REVHED

Please tell me you put a fuse in there somewhere. Wouldn't want the Seven to burn down.

The problem with the factory power window wiring is that the current for the motors runs through the switches. This causes the contacts to burn out and become dirty which slows down the windows. Doing what you suggest will only make them wear out quicker.

The proper way to do it is to use the factory wiring to trigger a relay and run the power from the battery through the relay. Safer and more effective.

rotary emotions

Hmmm... relays and fuses should indeed be a smart adition. "Simple" is nice, safe is better
The idea of a a strong wire running as a feeder isn't a bad idea as such, but you must always use correct fuses!

RotorMotorDriver

iTrader: (1)

Ok, so its back to the relay idea I had .

~T.J.

Rx7carl

As a matter of fact theres a write up on the internet. Cant remember who did it, but its very detailed and well written. And nice pic in the sig REVHED!

Metallic_rock

I just clean my window switches, the connectors and use di-electric grease on the inside of the switch. I've done that once and had no problem since. The windows go up and down quite quickly.

The only thing I can see running a separate wire for is a stereo amplifier. (which I have done)

Junia

Doesn't that method burn out the switch over time? I had some bad experience with an air horn that I installed on another car. I had the switch wired directly to the battery and over time the heat melted the switch, and next thing I know I was driving around playing the Godfather theme.

Metallic_rock

if you run a switch straight from the battery, yes, it can burn it out... recommend using a relay.

RotorMotorDriver

iTrader: (1)

Yeah, Ive seen that write up, but I cant remember where either...

~T.J.

jimmyrose99

how slow are we talking here? i dunno whats normal

RotorMotorDriver

iTrader: (1)

Ok, so if you wanted to wire in relays, where would you do it? Would you use the wires going to the switches? Ive never actually tried to wire in a relay before without following directions, but I understand how they work, so Im gonna try and see if I get this right...




Ok, so you would need two relays per switch, right? One for up, and one for down because the windows use a switching polarity type setup (or something?). If thats the case, then you would want to run the constant 12V or switched (maybe with another relay? lol) from the battery to terminal 87 on both relays. Ground would be 87A on both relays, with 85 as ground on the "up" relay, and 86 as ground on the "down" relay. Terminal 30 on both relays would go to the window motor. Then, terminal 86 on the "up" relay would be the input from the switch, and terminal 85 on the "down" relay would be the input from the switch...Right?

~T.J.

O 16581 72452 5

I'd just hold my revs up a bit while rolling the windows up after parking.

RotorMotorDriver

iTrader: (1)

Ok, so it would look like this (Kinda, lol) for one side. Red is power from the battery, white is ground, yellow are the wires to the motor, and blue is the input from the switch. This would work, right? So if I wanted to do this for both windows and have a relay to run off the ignition switch to get power from the battery, I would need like 5 relays, lol. Damn, thats a lot of relaying, lol. Plus relays are kinda loud when theyre used...I wonder where I could put them...Under the dash somewhere I guess...Anyway, is this right?

~T.J.

REVHED

That's pretty much it. Except there's no point in switching the input and ground around on the 85 and 86 terminals. You can run ground to 85 on both relays.

RotorMotorDriver

iTrader: (1)

Damn, I was close though. Not bad for my first try implimenting relays into something like this, eh? .

Ok anyway, so the fuse for the power windows is a 30 amp fuse, so I assume I can use 30 amp relays and safely handle the power? My plan is to use 5 30 amp relays. One to switch the power on to the windows, then the other 4 to control the windows. So from the battery Ill have like a 12 gauge (maybe bigger?) wire run through a 30 amp fuse, then through the first relay using the ignition switched voltage as the trigger, then on into the cabin where it will power the other 4 relays before finally powering the window motors. I think I have a plan, and all for less than $10 I will get faster, better windows .

This is something I wanted to do for a while (get the windows working better) because I plan on getting an alarm that has a window control module so it will roll up the windows and stuff, and with the way mine work now, they barely make it all the way up unless the cars running. Although, I know they work plenty fast when given a good 12 volts. When I had to roll them up after it was stolen and they had cut all the harnesses under the hood so I couldnt hook up a battery and use the switches, I just used a car battery and went straight to the plug inside the door at the motors. The windows sure do move quick when they have good voltage .

~T.J.

Parhelius

For all the people mentioning the use of a fuse when I posted this thread, yes your right, I forgot to add that bit of information in. - But I did mention that it's better to use a relay, but this is a quick fix. I have 20 amp switches running 15 amp wire, that is all that is required.

When you start upgrading to 30 amp cable it's unnessesary, as the original wire supplying the whole cars power can carry a max of 15 amps, so 30 amp is overkill just for the windows. I ran some 2.5mm 240V single core cable to supply the switches. And if a switch burns out under less than 15 amps of load, then there is a problem

(The 30 amp fuse allows both switches to operate at the same time, which means each individual switch can run at a max of 15 amps)

Parhelius

I have worked with industrial electricity, domestic electricity, and automotive electricity, and running a large cable to feed smaller appliances is safe and practical thing to do. I mean, whats better?? Having one 8 guage supplying everything, or 20 individual runs of 12+ guage?

If the cable is fused at the right current, there is no detrimental effect to doing that.

Kerry

I ran direct battery (fused) to my switches about a year ago. I had thought about relays, but I've had relays stick closed in the past. If that happens with the 2-relay setup, you're not going to roll the window up until you replace the relay and the fuse. No good in the rain. Also...to do it right, the relays should really be as close to the motor as possible, ie. in the door. Doesn't sound like much fun. Advantages and disadvantages to either method, pick your poison.

Kerry

Junia

What problem is everyone having with their power window?? I've never had a problem with the windows going up slow. The only complaint I really have is when the passenger side door gets closed a few times the mirror is facing the ground.....

REVHED

There's no need for the 5th relay. The power to the switches is ignition switched already so the relays won't energise unless the ignition is on.