98 V70 driver's door electric window issue

Post by **scot850** » 14 Jun 2018, 23:14

I had a call from a Volvo friend a few weeks ago to see if I had a spare master window switch as her friend who lives in Calgary was having an issue with the window dropping but then not raising again. She had had it checked by a repair shop and they diagnosed a bad master switch and were able to raise the window to closed position and then disconnected the harness plug for the front windows to prevent further issue until a replacement switch was fitted (at $400!!).

I swapped out the switch for a spare I had for the owner (car has less than 60,000 miles on it!!). Window worked ok if a little slow.

I got a text a couple of days ago to say the driver's window was playing up again and the switch was not working.

I am thinking that maybe bad luck with the used one, but it is possible something else is maybe burning out the switches. Only affects the driver's window.

I gave my friend a list of things to check from stuck or tight sliders in the window regulator, to spraying some silicon oil on the window channels to a broken rear guide.

The fuse is not blowing (if it did no windows would work). Could the motor for the window be drawing too much current and burning the switches out?

How do we measure the current draw on the window motor and does anyone know what a correct motor should draw?

Thanks,

Neil.

Post by **wizechatmgr** » 15 Jun 2018, 18:04

I'd silicone oil the heck out of the window channels before I did anything else. I've had slow moving windows that became buttery smooth doing this alone.

Post by **scot850** » 15 Jun 2018, 22:43

Appreciate the reply. Like you suggest sometimes you just have to start with the easiest possible solutions and don't over think it!

Thanks,

Neil.

Post by **MrAl** » 16 Jun 2018, 08:25

Hello there,

One way to measure the current is to measure the current of a working window motor like on the other side and then measure the problem window motor and compare readings.

At the moment i can only think of one way to measure these, but luckily i think you can measure both with the same meter connections. Someone else may have more info on this too.
The idea is to "disconnect" the battery positive terminal (engine off, ignition off) and place a current meter in series with the battery. You can then operate the 'good' window, note the reading, then operate the 'bad' window, note the reading, then compare notes.
I put "disconnect" in double quotes because you dont have to actually disconnect the battery but you do have to break the connection to the positive lead. That would require using a good jumper from the positive battery terminal to the battery BEFORE undoing the battery terminal, then undoing the battery terminal, so that after you undo the battery terminal the battery is still connected via the jumper. You would then connect the meter in series with the battery and the positive terminal wire, then remove the jumper, and that puts the meter in the circuit without actually disconnecting the battery. You can then take readings, then reverse the procedure to get the battery connected the way it was originally.
NOTE that if you make one mistake in disconnecting the battery and using the jumper and meter, you may accidentally disconnect the battery momentarily and that would reset all your monitors. This means you need a really good jumper probably one that bolts or clamps to the terminals not a cheap alligator jumper.
The way this would probably be done in a car shop is they would probably power the car (engine off again) with a 12v power supply though the OBDII connector, then disconnect the battery and connect the meter, etc.

Switches do go bad. Various problems come up but the most common is a dirty contact. If the switch comes apart and you can get it back together again sometimes you can clean them good and then put back together, maybe with some added dielectric grease. If the spring breaks then you cant fix it without getting new parts which is probably not possible. A junk yard would probably be the next place to visit.

Motors do go bad too, in various ways also. The brushes wear down and dont make good contact anymore. That makes the motor weaker. That would mean the window goes up slower. That would show up as less current and less power. They also develop shorted turns, but that's more rare. That would mean more current and less power.
They can also develop an open winding and if they have more than one winding then the motor might still work a little but will again be weaker.
Of course there is also shaft freeze. If the bearings are getting old the lubrication may be drying up, which makes the motor run slower and weaker of course. The solution here is to take it apart and clean and lubricate the bearings.

Post by **scot850** » 16 Jun 2018, 11:52

Why does it have to be on the +ve side. Could you not achieve the same by putting the leads on the -ve side from the battery to say the ground connection behind the headlight on the inner fender? When checking for current draw I normally disconnect the -ve lead and connect the leads between battery and -ve lead, but appreciate here we need power to run and test the battery so the battery needs to stay connected.

Many thanks for the reply and great info/suggestion. Would never have thought of checking it that way.

Neil.

Post by **MrAl** » 16 Jun 2018, 12:17

Hi again,

I guess you could check using the ground lead, as long as there is nothing else connected to the negative terminal once the battery is "disconnected" and the meter inserted.
Also, if you can get a hold of a DC current clamp meter, you might ba able to use that. For that test you just place the clamp around one of the leads going to the battery and then take readings ... no disconnecting needed.
Just have to make sure you surround all the wires from one terminal of the battery with the clamp or else you wont be measuring all of the current.
If you happen to measure an offset first (some current without any window motor running) then you can subtract that from the readings.
I would guess that you should use a meter with at least a 20 amp current measuring range. Those motors would draw significant current, although they are geared down too. Clamp meters usually go up into the 100's of amps.
If you buy a clamp meter though make sure it can measure DC current as many of them do not. They say "AC/DC" but they mean they can also measure DC voltage, although they cant measure DC current. If they measure DC current they always explicitly state that "DC current" not just "AC/DC"

Post by **scot850** » 16 Jun 2018, 17:19

Great info again, I'll pass the info along.

Neil.

Post by **MrAl** » 16 Jun 2018, 17:39

scot850 wrote: ↑16 Jun 2018, 17:19 Great info again, I'll pass the info along.

Neil.

Hi again,

I am happy you found it useful.

Just one more small note about the clamp meter. The Mastech MS2108 clamp meter is pretty good for the price. It has true RMS and surge readings. The surge reading helps if you need to catch a quick surge of current like from a home appliance when it is firce plugged in. It also has a display count of 6600 and goes up to 600amps.
The MS2108A on the other hand is cheaper but does not have the true RMS functions (as i have read) and does not have the surge readings and the max current is 400 amps. It is around 20 dollars cheaper however.

The clamp meters make it easier to measure current when a SINGLE wire is available for measurement, such as with a car battery. If there are two wires coming off one battery post though you have to surround both wires to see all the current. If you only want to see the charge current then you have to only clamp on the charge wire, if you can figure out what one it is.

It took me some 20 or 30 years before i bought a clamp on meter but i was never sorry. I didnt want to buy one originally because the DC current models were expensive and i definitely wanted DC as well as AC current operation because i do a lot of DC stuff. Mastech came out with their line of products and so the price came down and it became worthwhile for me to get one (the MS2108). They may not be a Fluke, but they work well enough to get the kind of readings we usually need which are accurate enough for most purposes.

Best of luck to you with your project.

Oitsujosh · Post by **Oitsujosh** » 16 Jun 2018, 18:23

Good evening, I have 15+ years in the Autoglass biz. It have been awhile since I have done one of these, but I know a common issue is the blue clips that attach the window to the regulator tend to crack and split. If they appear to be fine, I would clean the old grease from those tracks as best as you can. Then put some new grease in them. That and siliconing the window felts as suggested as before. In my experience I've never come across a side window motor go bad in a volvo before. Not saying it couldn't but feel it's fairly rare. If those blue clips are broken I have gotten them at a dealer in the past for fairly short money and normally had them on hand, at least they used to

. The switches are also common to go. Switches in the back of my xc70 are flaky, but little one are back there now and I have the window lock most of the time anyhow.
Sorry this got a little long but hope it helps.

Josh.

Post by **scot850** » 16 Jun 2018, 19:37

Thank you both for the helpful suggestions.

I know about the sliders and the window system (including the fracturing lower mount on the rear window guide) but was looking for anything else I could suggest as I don't have the car here to check personally. I have a friend who is a mechanic and it is her friends car that is the problem child. She is going to check it over this weekend while visiting from out of town.

Much appreciated.

Neil.