Headlight switch or bad relay?

Post by **dosbricks** » 06 Sep 2012, 11:58

Back with another aging 850 issue-- it's a '96 GLT with 145k.

For the past few months the headlights will occasionally not work when turning on the switch the first time--but would come on after a few tries. Last night my wife repeatedly switched them on but could not get them to work, and she drove home by holding the high beam lever toward the wheel (cool that she had the presence of mind to figure that out). I went out to the garage and acuated the switch about 20 times and it worked perfect every time.

Since she tried shutting the car off and restarting with no effect, it would not seem to be an ignition switch issue. I'm wondering if it is the HL switch or the rely in the fuse box? Heat doesn't seem to be a factor because the car was hot under the hood in the garage when I tried to get a malfunction. No other circuits seem to be involved--everything else is normal.

Would appreciate any suggestions as to how to proceed before I buy the wrong part first-- my track record shows a penchant for that. Thanks,

Ken

Post by **jblackburn** » 06 Sep 2012, 12:19

I dunno, it kinda sounds like an ignition switch issue to me. Starting and restarting the car, mine would STILL not work sometimes.

See if it will act up again, and then try fiddling with the key a little bit once the engine is started.

Post by **cn90** » 06 Sep 2012, 12:48

- Remove the HL switch (insert a flat blade screwdriver wrapped in cloth and gently pry it out).
If you can get behind the HL switch and push it out, it is also OK.
- In my case, I had the exact same symptoms, the HL switch is bad (a well known issue).

- The fix:

1. New HL switch is about $60, used about $20 on ebay.

2. Fix it. I used a very small wire (similar to the solid copper wire found in telephone wire, the kind of wire they run inside the house telephone wiring).....drill some small holes on the side of the HL switch. Pass the small wire through so it holds the broken part together. So far so good.

I wish I took a picture to show you, but I did not take any photo!

Post by **dosbricks** » 06 Sep 2012, 13:38

I have told my wife to call me next time it won't work and I will try the key wiggle and relay tap which I read about using the search option.

I will also pull the switch and look for anything broken/repairable as I like the cheap/simple when it's an option. Thanks for the tips, guys.

Post by **cn90** » 06 Sep 2012, 14:23

I think you should take proactive measure and take care of this problem upfront, nothing worse than driving in the middle of the night and the whole HL system went dark, been there done that. Very very scary!!!

Removing the HL switch is 1 min deal, very very easy.

I took this pic from the web to show you what I did:
- The tabs are very flimsy, they break with time (Green arrows show broken tabs)
- The back of the switch will come apart (Blue arrow)
- The fix is very very simple, drill a tiny hole using bit less than 1/16" in size.
Make sure you drill only 1mm deep!!! Anything deeper: you risk damaging the internal anatomy.
- Then use the thin telephone wire (use insulated wire so it does not cause shorts inside) and pass it through like this:

Hole #1 ---> inside switch ---> hole #2 (on the other side) ---> around the Back side of the HL switch and gently twist-tie it (2 turns is enough, anything more than that will break the telephone wire).

HTH.

: VolvoHL.JPG (23.23 KiB) Viewed 6469 times

Post by **rmmagow** » 06 Sep 2012, 14:31

Personally, I'd just buy a new switch if it were my wife's car. Having the light's go out in a snow storm at night would cause my wife to start dis-liking the Volvo and the one that gave it to her to drive

Post by **cn90** » 06 Sep 2012, 14:39

Actually new switch is no warranty, it is just flimsy design.
Believe it or not, the fix I mentioned above is a permanent fix!

Post by **rmmagow** » 06 Sep 2012, 15:00

Hmm, yanking my switch this weekend! No trouble so far but I sort of remember my v70r acting up. This car's the same age.

Post by **dosbricks** » 06 Sep 2012, 15:01

cn90, Excellent post! I can see exactly what you are refering to. The car will be available to me tomorrow, and I will remove the switch and look for broken tabs. I repaired a plastic rear seat ceiling light toggle on the S70 ten+ years ago by drilling and inserting a steel splint--just minor internal surgery--still working fine.

rmmagow, I deeply appreciate the point of view, but it only snows in deep South Texas once in a lifetime.

dos

Post by **dosbricks** » 07 Sep 2012, 15:26

cn90 wrote:I think you should take proactive measure and take care of this problem upfront, nothing worse than driving in the middle of the night and the whole HL system went dark, been there done that. Very very scary!!!

Removing the HL switch is 1 min deal, very very easy.

I took this pic from the web to show you what I did:
- The tabs are very flimsy, they break with time (Green arrows show broken tabs)
- The back of the switch will come apart (Blue arrow)
- The fix is very very simple, drill a tiny hole using bit less than 1/16" in size.
Make sure you drill only 1mm deep!!! Anything deeper: you risk damaging the internal anatomy.
- Then use the thin telephone wire (use insulated wire so it does not cause shorts inside) and pass it through like this:

Hole #1 ---> inside switch ---> hole #2 (on the other side) ---> around the Back side of the HL switch and gently twist-tie it (2 turns is enough, anything more than that will break the telephone wire).

HTH.

VolvoHL.JPG

Okay, reporting back. The plastic hook tab was indeed broken on one bottom corner as seen in the attached photo. I had some phone wire left over from building our house, so I drillled 3/64" holes, but the wire would not pass an obstruction on both sides about 1" in from the bottom. I'm going to suggest here that the 850 switch may be a bit different internally than the S70. I recall the S70 had most of the failures in my archive search.

My fix: I took the switch apart being careful not to break anything additional. Inside I could see the reason the wires would not pass was because of the housing part of the rotational switch. It was obvious that these switches would break over time because of the internal spring pressure of the knob travelers against the back section of the switch. All contacts looked clean and still oiled with the factory di-electric grease.

With it apart I could determine that it was clear to drill 2 holes in the back corners and insert pins (shiny spots in the photo) made of finish nails cut to 3/16" length and press fitted. Finished up by grinding the heads down a bit and covering them each with a drop of Gorilla Glue to ensure no back out. All functions are working at present. I'll have to wait to see if another no-light "event" happens, but with luck maybe I'll be home free with this fix.

Thanks cn90 for the confidence to take a look inside to see what was going on.