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Horns, Gear, and Equipment => Technology => Topic started by: timothy42b on Jul 14, 2017, 10:24AM



Title: Maybe dumb car repair idea
Post by: timothy42b on Jul 14, 2017, 10:24AM
I have a 91 beater Volvo that's been a challenge to pass inspection every year, and we're coming up on the time again.  Each time I say well maybe one more year.  But we have three people working and two cars, need to keep both running or give up and buy something newer. 

There are several electrical problems but the one that will fail inspection is the driver's side power window.  The other three work fine.  I've cleaned the switch, it is actually the connection between switch and harness. 

So here's my maybe dumb idea:  I swap the wires between the driver's window and passenger window at the master switch.  I can't just swap connectors, all four are unique, so it's cut and splice.  There are four wires to each switch:  power, ground, up, down.  I have a decent quality crimper and choice of butt splice connectors and male/female connectors (which the autoparts guy recommended). 

My daughter is sure this will result in neither window working.  I don't see any theoretical reason why, if done slowly and carefully, this shouldn't succeed.  But I've been wrong before. 


Title: Re: Maybe dumb car repair idea
Post by: trombonemetal on Jul 14, 2017, 10:43AM
I love creative car fixes but why not just fix or replace what's broken? Junk yard? Multiple switches for one window might mess up your plan. Your daughter has a point about possibly messing up the other window too.

I'm doing a CV joint on my 03 XC70 tomorrow morning. Hopefully that's not a fiasco.


Title: Re: Maybe dumb car repair idea
Post by: robcat2075 on Jul 14, 2017, 10:45AM
I dimly recall a previous discussion of the window problem.

Why can't you splice in a new harness if the current one is not making contact?


Title: Re: Maybe dumb car repair idea
Post by: timothy42b on Jul 14, 2017, 10:48AM
If there were an easy way to get a new harness for a 1991 car I would consider it, though it means splicing 20 wires instead of four. 

I'm doing a junk yard run tomorrow and might come up with something.  Trouble is, any car old enough to have parts that fit is old enough to have the same systemic problems. 


Title: Re: Maybe dumb car repair idea
Post by: BGuttman on Jul 14, 2017, 10:57AM
Is this a 240 or a 740?  I have a couple of junkers here.  My 1991 740 and a 1990 240.  I might be able to salvage a couple of parts...


Title: Re: Maybe dumb car repair idea
Post by: Bimmerman on Jul 14, 2017, 11:54AM
if there's one in the junkyard, just take a big set of shears and cut the harness a few inches from the switch connector. Grab that pigtail, the switch, and then cut/splice the pigtail into your existing harness.

Just go slow, take your time, and buy good quality crimp connectors/cutters/strippers/crimper.

A multimeter won't hurt either to check connectivity.


Title: Re: Maybe dumb car repair idea
Post by: robcat2075 on Jul 14, 2017, 12:15PM
Can the wires be removed from the harness and hard connected to the switch?


Title: Re: Maybe dumb car repair idea
Post by: timothy42b on Jul 14, 2017, 12:28PM
Can the wires be removed from the harness and hard connected to the switch?

There are four switches that clamp into the module. 

the connector module fits in from underneath. 

The switches have male pins on the bottom, but they don't extend below the enclosure.  The connector has female pins that likewise go to the edge of a square box connector.  The connector fits into the underside of the switch such that the box goes inside and the pins connect.  That was my first thought but I could not figure a way to make a connection. 


Title: Re: Maybe dumb car repair idea
Post by: BGuttman on Jul 14, 2017, 12:41PM
Sounds like a variant of the Molex connector.  The female pins have a tab that keeps them from slipping out of the connector block.  In order to remove the pins you have to release the tab.

Here is a female pin.  Note the tabs about halfway along the connector (the back end of the pin is a crimp connector):

(http://www.jameco.com/Jameco/Products/ProdImag/741677.jpg)

I have a tool somewhere for removing Molex pins from the connector blocks.  It goes in from the "business" side and closes the locking tab so the pin can be removed.


Title: Re: Maybe dumb car repair idea
Post by: robcat2075 on Jul 14, 2017, 03:48PM
So both a switch on the door and a switch on a center console have failed?


Are you required to have a window to pass inspection?


Title: Re: Maybe dumb car repair idea
Post by: timothy42b on Jul 14, 2017, 04:39PM
So both a switch on the door and a switch on a center console have failed?


Are you required to have a window to pass inspection?

The driver's door panel has four switches for four windows.  The other three windows have one switch each.

The requirement to pass is only to open the driver's window.  Maybe if you get stopped by police?  The other three can be nonfunctional, although in my case that would apply only to the driver's switch.  The passenger could use their own switch.

And, in this weather, they'd have to.  Did I mention the AC hasn't worked in years?  Nor the clock or radio, etc.  It wasn't in great shape when we got it, but it seems to hang in there forever, dying a piece at a time.  My wife is two miles from work and I'm six, and we don't drive it much farther.


Title: Re: Maybe dumb car repair idea
Post by: robcat2075 on Jul 14, 2017, 05:53PM
Can the male pins be fattened up somehow to make for a better contact in the female side?


Title: Re: Maybe dumb car repair idea
Post by: BGuttman on Jul 14, 2017, 08:25PM
Can the male pins be fattened up somehow to make for a better contact in the female side?

Some Molex male pins can be spread; some are solid and can't.

Usual repair technique is remove and replace the male or female pin.  Needs a special tool (mentioned above).


Title: Re: Maybe dumb car repair idea
Post by: robcat2075 on Jul 14, 2017, 08:42PM
Can the window be operated by sticking a u-shaped wire into holes of the connector?


Title: Re: Maybe dumb car repair idea
Post by: Radar on Jul 15, 2017, 06:01AM
Sounds like a variant of the Molex connector.  The female pins have a tab that keeps them from slipping out of the connector block.  In order to remove the pins you have to release the tab.

Here is a female pin.  Note the tabs about halfway along the connector (the back end of the pin is a crimp connector):

(http://www.jameco.com/Jameco/Products/ProdImag/741677.jpg)

I have a tool somewhere for removing Molex pins from the connector blocks.  It goes in from the "business" side and closes the locking tab so the pin can be removed.

I think Bruce is on to a possible solution here, with the right tools these molex connectors are relatively easy to repair.  You need a pin removal tool, and a crimper and you can buy bags of replacement pins.  If the connectors have been loose for a while they may have drawn excessive current and damaged the wiring insulation, if that's the case run new wires of the same gage on the outside of the harness and wire tie them in place (cut the old wires back and tape them so they don't make contact with anything)


Title: Re: Maybe dumb car repair idea
Post by: Steve Foote on Jul 15, 2017, 07:16AM
I have done car repairs for many years, mostly by trial and error. I have often bought the same parts may times due to breakage while attempting to get something installed.

Since the advent of YouTube my success rate has improved dramatically.

There are several YouTube videos on Volvo window switches. These may or may not apply to you.

I had a similar problem on a 2000 Impala. Replaced the entire master switch which took about 30 minutes and $90.00.

I am sure that all of these are carefully designed so that the driver's window is always the first to malfunction!

Hope you can get it repaired and through the inspection with no further issues.


Title: Re: Maybe dumb car repair idea
Post by: timothy42b on Jul 15, 2017, 09:16AM
One more symptom:  I keep the switch module loose in the door handle.  I can always make it work by pulling it out, getting a finger under the connector for that switch, and pulling up on it.  Of course that's a pain, especially when my wife has driven and pushed it down deep into the door.  So that leaves the diagnosis a little vague.  It could be the pins not holding, or the plastic case around them that no longer fits tightly.  (and yes, I tried a kluge job with rubber bands and tooth picks trying to put some compression on it; no luck) 

Yes, replacing the pins seems the ideal solution, provided the plastic case still snaps tightly, and I don't know how to test that.  Swapping for the passenger door is an inelegant solution.  There must be some way to get new pins but I haven't found it.

Anyway, progress.  At the auto salvage yard today I found several Volvos.  Only one, a 1989, had a window switch with connectors that seem to match mine, so I snipped the wiring harness and took the whole thing.  $10.99.  Plus a bunch of tax and fees.  So now my plan is to splice in the matching connector onto the drivers switch wires.  If that works I'm done.  If not, I buy some pins, and I now have 12 others to practice on (the three other switches in the module).   If there were more access I'd just solder on female pins that are even close, but we're talking 4 pins in a half inch square, buried deep.   I can do almost all the work in my basement with good light and room to work.  It's a 28 year old component, it's not unlikely the salvage yard one is bad too. 

I don't have time to finish this weekend, work calls, hopefully I'll try for next. 


Title: Re: Maybe dumb car repair idea
Post by: boneagain on Jul 15, 2017, 10:43AM
Next weekend?  PM me to remind me to bring a pin tool to rehearsal.

More folks should join Bonefire... not only do we play the classics and sometimes even win, but enjoy numerous other digressions too  :evil:


Title: Re: Maybe dumb car repair idea
Post by: BGuttman on Jul 15, 2017, 11:36AM
Next weekend?  PM me to remind me to bring a pin tool to rehearsal.

More folks should join Bonefire... not only do we play the classics and sometimes even win, but enjoy numerous other digressions too  :evil:


I would love to, but it's an awfully long drive from here. :)


Title: Re: Maybe dumb car repair idea
Post by: timothy42b on Jul 23, 2017, 01:56PM
Time for an update.

I spent last week at Camp Blanding Florida doing Army stuff.  Ever been there?  Fly into Jacksonville or Gainesville, drive a couple hours into the woods.  They have a perfectly round lake, someday I'll google why it's so round.

So now I'm back.  Saturday was Bonefire (back on tenor playing third after two straight weeks exclusively on alto) and mowing the lawn in 99 F weather.  Today I fixed the car.

I carefully marked every wire on the switch with tape, and every wire on the junkyard connector.  I cut off the old connector and put male bullet connectors on four wires and female on the other four.  Snapped them together, and the window works.  Then I taped over all the connections and stuck the switch back down inside the door. 

I don't know how long it will last.  But the car's been on borrowed time for a good while.  We'll see. 


Title: Re: Maybe dumb car repair idea
Post by: robcat2075 on Jul 23, 2017, 02:12PM
Hooray for successfully-connected wires.


Title: Re: Maybe dumb car repair idea
Post by: boneagain on Jul 23, 2017, 07:11PM
Yay Tim!


Title: Re: Maybe dumb car repair idea Maybe the end of the Volvo threads
Post by: timothy42b on Oct 18, 2017, 08:28AM
This may finally be the end of my bringing my Volvo woes to this forum.

It's started overheating, shortly after doing enough repairs to pass inspection.  That would have cost more but I repaired the window switch and the bad connections on front turn signal and back brake light myself. 

The shop diagnosed a bad water pump and replaced it.  That made no difference.  It overheats and the heater blows cold air, then it seems to fix itself and the temp gauge comes back down and the heater works, then everything repeats, all within a couple of miles.  Clearly there's a coolant blockage that comes and goes. 

This morning I squeezed the radiator hose and it was pressurized rock hard.  Seems to be exhaust gas getting into the coolant.

That means a blown head gasket, I guess, and that's not economically repairable on a 1991 high mileage car.  The mechanic we use agrees with me.  He did say I might get some local travel running it without a thermostat and maybe trying one of those stop leak products.  The gasket itself is only about $60 but there's apparently a lot of labor involved in changing it. 


Title: Re: Maybe dumb car repair idea
Post by: BillO on Oct 18, 2017, 09:00AM
Replacing the head gasket on and overhead cam engine is a big job.

I remember doing the job on my old 1965 Valiant with a 225ci slant 6.  Drain the coolant, remove the hose, remove the plug wires, remove the head cover, unbolt the head, clean off the old gasket, put on the new gasket then follow the above steps in reverse.  Took about an hour.  Nothing like an old push-rod engine for simple maintenance.


Title: Re: Maybe dumb car repair idea
Post by: BGuttman on Oct 18, 2017, 09:09AM
Sounds like what happened to my 1991 740.  It was death by 1000 papercuts.  All kinds of little things hit.

The head gasket is a simple thing but you almost have to remove the engine from the gasket to install.  I think $1000 is not unheard of in some dealer shops.  It's a 2 weekend project if you try it yourself.  And that's on a simple 1991 engine rather than something more modern.


Title: Re: Maybe dumb car repair idea
Post by: timothy42b on Oct 19, 2017, 07:28AM
Based on the mechanic at the shop and some internet advice, I thought it was worth seeing if it would overheat less if I took the thermostat out.

It's easy on a Volvo, the upper hose is right there with nothing in the way.

Yeah, not.

Two nuts hold it on.  One came off easily, the other defied my efforts for most of the day, but finally came off, a bit mangled but intact.

Of course the thermostat has to go back in sans guts, the gasket is too small to seal alone.  So I removed the thermostat center.

But then.  All the time I was working on the difficult nut, I was sweating over rounding it completely or snapping the bolt shaft.  (yeah of course I bought a new nut before reinstalling.) 

So of course when I put it back together, the other bolt snapped off.  Not sure why, I was using my short 3/8 inch ratchet, not the 1/2 breaker bar that worked on the other one. 

Sigh. 


Title: Re: Maybe dumb car repair idea
Post by: robcat2075 on Oct 19, 2017, 08:00AM
My friend's dad used to say, "There will be cars in Hell."