Car is a 1982 GLT. I have just put it back in service after a six month layoff. The rear window defroster was working before the layoff but has now stopped.

Is there a good troubleshooting guide/video for this item on this two door car somewhere online?

I have found a pretty good one for a 245 wagon but if I could get one for the two door I would appreciate a direction.

Bob

The first thing that I would check is the switch.

If it is a momentary switch, try touching a wire across the terminals.

If it is an on/off switch, put a jumper wire a between the two connectors.

The next thing to try is to connect power directly to the device.

Lastly, add a direct connection to ground.

These steps are usually quick and easy.

Okay. I know that the switch is operating. I am getting 12 volts at the switch and it opens and closes properly.

No voltage to the defroster so it looks like I will have to pull the plastic covering to get at the connector.

I would like some information on removing these panels because they are old plastic and I don't need to break them by pulling on the wrong end. Will get back later.

bob

You can measure voltage at the rear window by toutching carefully the heating wires on the left side of the car.

This is where the current is coming in.

If there is near 12 volt then the ground connection is the problem.

Are you talking about the 'input' wire? Or do you mean the wires that are actually traced on the window surface. I checked what I thought was the 'input' wire on the right hand side of the car. Didn't realize that its identical cousin was on the left hand side.

From my schematic it looks like the input wire goes to the grid and then exits to ground. I am taking it from your suggestion that the input occurs on the left side, goes through the grid and then exits to ground there. Am I following that correctly.

I have a couple of pictures of the two inputs but I will probably not be able to get them ready to send for this message.

bob

On my 1982 the input is on the left side of the car ( right side when on your knees on the back seat).

The vertical printed strip should be visible and less fragile to touch.

Roland,

I didn't get any joy touching the positive lead of the meter to the vertical printed strip or poking a needle into the physical connector and measuring there.

I have power to and from the switch.

So the break is between the switch and the grid.

The schematic shows a yellow wire going from the switch to the grid through two connectors. I know that one of these connectors lives behind the plastic panel that is covering "C" roof pillar. But I don't know where the other one lives. Any ideas on that?

Bob

Here are a couple of pictures of the two side connectors. Can I use these to measure voltage instead of endangering the grid? Having some problems uploading the images. Hope they arrive. I think it is here but am not sure.

I only see the one picture for the right side (grounded). I know I had a picture myself somewhere, so I went pawing through the pile, but only found one from a 244, not my 242. I'm pretty sure the wiring for power comes in on the port side and ground is on starboard on all body styles, but that's not so important as seeing a 10-12V difference between the sides.

We've had three 83 240s which all had a timer relay in the rear window heater. My map for the 82 shows just a switch.

My approach would not be to probe the film. I'd slip and scratch right through it and then kick myself up the stairs. Instead I'd poke a sharp needle through the vinyl sheath on the copper strip connecting the window to the wiring.



In the past I've had some luck moving a small compass over the grid from the outside to see how many were still working. It is tricky because the compass wants to be level for its bearing to work freely.

PS if you've a satisfactory conclusion to the light switch story, never mind, but if not, update your thread, and I'll return to it with a bunch of pics I found from when I restored an original (old type) switch. I seem to recall some forum dissatisfaction with the aftermarket replacement part.
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Art Benstein near Baltimore

"Feel free to point out my ignorance but don't insult my intelligence."

I forgot to mention the relays. I have been reading about them but I cannot see any relay on my two schematics from Haynes and Bentley. I checked Bentley for later models but still could not find a relay in the circuit right through to 1986.

Ha! I see the same as you, not until 1986. Baffled, I checked our two '83 240s remaining, and find the switches as I remembered with the rounded edges (as opposed to the older type in our '79) but they are not momentary, or spring loaded. No relays. Sorry for the BS. Shows how little I use them.
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Art Benstein near Baltimore

"...people will always choose a simple lie over a complicated truth, because the lie has one unbeatable advantage: the truth always has to stick to what actually happened, whereas the lie just has to be easy to believe" - Fredrik Backman

Hi Art,

I hooked a long lead from the battery ground to the multimeter and checked for power at the port side connector using a needle and carefully poking the grid vertical connection without success. No power.

I will try the starboard side just in case I have a maverick that got wired the wrong way around but don't have much expectation of success there either.

I do have power to the switch and leading away from the switch. So I am losing power between the switch and the grid connector.

My schematic shows a yellow wire and two connectors between the switch and the grid. Because of your picture I have seen one of the connectors that lives behind the plastic covering on the "C" pillar.

Before I start tearing into that do you have any idea where the other connector might be living---hopefully in a more accessible location?

Bob

Hi Bob,

I feel pretty safe in telling you the yellow wire runs from that left side C pillar connection down over the wheel arch and makes its way in a vinyl sheath along the floor pan inside of the rocker panel (under the carpet) all the way to the firewall to the left of the driver's left foot. In the later cars there's a connector there to join the harness going to the rear lights and trunk with the harness connected to the center console where your switch is, but I don't know what it looks like in the 82. I'd first look for the yellow wire in the bundle that comes up by the fuse panel, going back.

Think about the body or paint work I think you mentioned. What may have been disturbed? Any floor pan work? Rust? Take the long plastic threshold up and look under the carpet under the door.
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Art Benstein near Baltimore

If you have any trouble sounding condescending, find a UNIX user to show you how it's done. -Scott Adams

Hi Art,

I have been thinking about the fact that I removed the instrument panel when I could not get the headlight switch nut to release. The clock stopped working until I figured out that it had a connector to the instrument panel that I had neglected to put back in place.

I am thinking of taking out the instrument panel to take a gander in there and to see if there is any kind of connection that I might have failed to make that might have impacted the rear window defroster.

I will try to find the yellow wire given your information on its route from the window grid to the switch.

I suspect the break is somewhere around the instrument panel area rather than at the connector at the 'C' pillar and it probably has something to do with my rumbling around behind the instrument panel.

Thanks again for your valuable input.

Other than these minor issues the old bus is running like a Swedish clock!

Bob

Roland said that the power comes in from the port side and exits to ground through the starboard side and that fits with your analysis.

So far I have been unable to find any power to the port side at the grid but I do have power to the switch and from it---I blew a fuse going over the switch connections today.

I have not been able to find power at the grid on the port or starboard side. My thinking is that I should have full power on the port side and little or no power on the starboard side. Do I have that figured?

I will try again today, piercing the insulation of the connector to get a contact. I was trying to get a contact by touching the solder joint but my ground was not all that trustworthy. I will try again and run a wire to the battery ground.

If I do not find power then I have to assume there is a break between the switch and the grid. But I will get back to you before going there.

I don't know where the connector points are for the run from the switch to the grid but I can see one from your picture. Thanks a bundle for that--nice to actually see what is there before I try to take out the plastic covering.

The picture of I have of the port side is identical to the starboard side, by the way.

I would love to see your rebuild pictures of the headlight switch if it is not too much trouble to bring them up. I did buy another switch for $75CAN from a local wrecking yard proprietor who is the unofficial Volvo presence on Vancouver Island. Maybe I should have contacted the dealer, but the switch is a new one, not used, and usually the price will be high from the dealer.

bob

On the port side, not the starboard. There is only one port and one starboard :). I will give it a try in the morning and see what I can find. Regardless, thank you.

bob

Oxidation.
That grid, a thin film is 36 years old. They fail. It's amazing it worked so long.

Hey, it's a Volvo!

Switch is lighting up. It is an on/off type. I would guess that it is okay. I suspect the body shop guys might have pushed something aside at the connector to the warming grid so I will start there and see if I can detect power or see if anything is broken. Thanks for your input.

Let us know what you think is "pretty good" for the 245 and maybe we can point out the differences from your 242.
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Art Benstein near Baltimore

Birds are grouchy in the morning because their bills are over dew.

I forgot to mention that I had the car painted during its layoff and this could definitely be a source. I am going to see the autobody repair man next week to see if he had to do anything around the connections at the rear window.

Just being a bit lazy, Art. The directions I received are elementary. Check the fuses, check for power at the defrosting grid, find the ground if there is power there.

It is here that the author goes into what to do on the 245 and starts getting into tail-gate trim, etc. I just thought if somebody on the forum had laid out a procedure I would go for it.

p.s. I am going to re-install the clock today. Thanks for your information and recommendations.

Bob