Amazon: headlights

[jpws]

My headlights, both normal and high beam, on my '68 Amazon are not working properly. They mostly do not work but sometimes the normal beam works again. The high beam works when using the switch on the steering wheel.

I assumed it was an issue of damp in the footswitch (as it was damp in the drivers footwell). Now dried out and I have checked the footswitch with my voltmeter and the switch seems to be working as it should.

After reading some previous posts on here I tried joining the red/yellow and red/grey wires from the footswitch together to check if that made it work. However this didn't help.

I have also tested for resistance between the wires at the footswitch, as well as at the headlights. And it appears that all 3 wires are connected together, i..e I get no resistance when testing these, even when the lightswitch is off! So I am wondering if all three cables (normal, highbeam and earth?) are all connecting somewhere. I also read in previous posts, and on the wiring diagram, that there is a 6 connection box somewhere, so am wondering if something is wrong there. Where can I find that connection box? Is it on the nearside engine bay wall, next to a relay switch?

I have replaced all the fuses a short while ago and added some conductive paste. The lights were working with the fuses.

It's odd that the fault is intermittent so that suggests to me there is a loose connection. But then finding all the wires interconnected makes me think something else is wrong. But I'm no electrical expert, just tinkering.

Thanks for reading this lengthy message.
Any suggestions where to look and what to do next would be much appreciated.

[volvogv]

You are correct that there is a bad connection somewhere. I'm an electrical guy so I'm going to help you track this. First let me explain the difference between volts and resistance on your test meter. The volt meter measures voltage present from your car's electrical system. The ohms measures electrical continuity. If you try to measure continuity when the system is powered up, you're going to get false readings. Also the electrical components in your car can fool your meter into seeing weird things like all 3 wires being connected. The six terminal box you refer to is the connector set on the wiring harness. There are a few scattered around. Also, the headlights are not fused. Let's walk through the problem:

- Unplug the headlight. With your meter set on low ohms scale, measure across the headlight terminals (low beam and common) then (high beam and common). If the lamp filaments are good you will see a reading of maybe 100 ohms or so. If you see zero then you have a burned out bulb.

- With the headlights still out, set your meter to volts. Clip your black probe to the chassis and the red one to the headlight switch (black wire). Do you see 12 volts? if not the check the wiring at the key switch. (note: the key doesn't need to be on for the headlights).

- Move the red test lead to the yellow wire, pull on the headlight switch. Do you see 12 volts? If not, then your switch is bad.

- Get an assistant to sit in the cabin and move your setup to the dipper switch. With the headlight switch on, you should see 12 volts on the yellow wire. Move your test lead to the red wire. Have your assistant operate the dipper switch repeatedly. You should see 12 volts come and go. Move to the grey wire and repeat. You should see 12 volts come and go. If you don't get these results then you have a bad dipper.

- Move your setup to the headlight plug. Ground your meter to the chassis. Repeat the same test you just did, but put your test lead into the connector pins. Center pin is ground so skip it. On either outside pin you should see 12 volts come and go when your assistant operates the dipper switch repeatedly.

One of these tests will fail. It's your job to find it. Good luck and let us know what you find! Don't forget to put your headlights back in.....

[jpws]

Originally Posted by volvogv

You are correct that there is a bad connection somewhere. I'm an electrical guy so I'm going to help you track this. First let me explain the difference between volts and resistance on your test meter. The volt meter measures voltage present from your car's electrical system. The ohms measures electrical continuity. If you try to measure continuity when the system is powered up, you're going to get false readings. Also the electrical components in your car can fool your meter into seeing weird things like all 3 wires being connected. The six terminal box you refer to is the connector set on the wiring harness. There are a few scattered around. Also, the headlights are not fused. Let's walk through the problem:

Thanks volvogv for explaining this, much appreciated. I'm slowly learning, thanks for your patience. So I tried to follow your instructions, see my comments below.

Originally Posted by volvogv

- Unplug the headlight. With your meter set on low ohms scale, measure across the headlight terminals (low beam and common) then (high beam and common). If the lamp filaments are good you will see a reading of maybe 100 ohms or so. If you see zero then you have a burned out bulb.

Bulbs working.

Originally Posted by volvogv

- With the headlights still out, set your meter to volts. Clip your black probe to the chassis and the red one to the headlight switch (black wire). Do you see 12 volts? if not the check the wiring at the key switch. (note: the key doesn't need to be on for the headlights).

Reading 0 volts. Any advice on where and what to check at the key switch? Which parts to check? I think I saw a wiring diagram once for the key switch, will have another look.

Originally Posted by volvogv

- Move the red test lead to the yellow wire, pull on the headlight switch. Do you see 12 volts? If not, then your switch is bad.

Reading 0 volts, although not entirely sure what the yellow wire is as my wires have been painted. I can make out red (highbeam), black (I think), and possibly grey wires. Maybe my Amo has been rewired at some stage? When using the high beam lever on steering column I read 12 volts.

Originally Posted by volvogv

- Get an assistant to sit in the cabin and move your setup to the dipper switch. With the headlight switch on, you should see 12 volts on the yellow wire. Move your test lead to the red wire. Have your assistant operate the dipper switch repeatedly. You should see 12 volts come and go. Move to the grey wire and repeat. You should see 12 volts come and go. If you don't get these results then you have a bad dipper.

Not tested the footswitch yet, as this is all wrapped in electrical tape and I only recently tested the foot switch which appears to be working. I can test if this is crucial.

Originally Posted by volvogv

- Move your setup to the headlight plug. Ground your meter to the chassis. Repeat the same test you just did, but put your test lead into the connector pins. Center pin is ground so skip it. On either outside pin you should see 12 volts come and go when your assistant operates the dipper switch repeatedly.

Not done yet. I don't have a center pin. I think there is an issue at the main headlight switch. When I turned the switch (to adjust the brightness of the odometer lights) the main headlights came on and once on I could use the footswitch to turn on highbeam and switch back to normal beam. However once I turned off the headlights and then back on the lights were off again. I took the switch out from the dash and looked at it. When turning the switch (to adjust odometer lights) white powder falls out. I am wondering if some insulation inside it has rotted away? I am also wondering if I can connect some of the wires and turn the headlights on, to check if it's the switch or the wiring. Next job I've planned is to carefully label all the wires and the pins on the switch and take the switch out and inspect it more carefully.

Originally Posted by volvogv

One of these tests will fail. It's your job to find it. Good luck and let us know that you find! Don't forget to put your headlights back in.....

Does the above proposed next step make sense, or should I look at the key switch first? Any pointers to which bit of the keyswitch/light switch to look at would be much appreciated as that's stuck under the dash with lots of wires. So don't want to disturb the wiring too much.

Thanks for your help. Very much appreciated.

[volvogv]

Powder is not a good sign. You have corrosion going on inside your headlight switch. Consider buying a new one.

You read 0 volts at the black wire on the headlight switch. Assuming your meter is properly set (volts range for 12 DC) and the black lead is properly grounded to the car chassis (Make sure its on bare metal), then we need to look further upstream. Make sure your meter is working by putting your leads across the battery terminals.

Even if electricity is challenging, the good news is the Amazon has such a simple electrical system that we should be able to work through it.

Now...Based on what you've told me, the front marker lights and rear tail lights should be dark when you pull on the switch, correct?
The instrument lights are dark, correct?

If you have a standard shift late model Amazon then you should be on page 192 of the Haynes manual. Look at OBJECT-45 (headlight switch), and note the black wire that runs to OBJECT-46 (Key switch). At the key switch there should be TWO black wires on the same terminal. Did one wire come off? The other black wire goes to the battery and the car won't even run if this wire has no power. Without being able to see it, my guess is that the black wire from the key switch to the headlight switch is broken or loose. Sometimes it helps to wiggle a wire to see if it's intermittant.

Before you can go any further you must get power to that circuit.

Standing by.....

[jpws]

Thanks again for your helpful words.

I am considering getting a new switch, but I'd like to be sure that's where the problem lies before going ahead. Also would like to keep the car as original as possible, so would prefer to mend the switch, but seems like the switch is a sealed unit without easy access.

I was slightly confused I think and measured the wrong black wire (in the light fitting, not by the light switch). So I have no measured right by the light switch and am getting around 5 volts on the black wires. (It's a 12V car, but with alternator).

The marker lights and rear tail lights are all working fine when I pull the switch one and/or two stops out. The instrument lights are working fine and I can adjust brightness by rotating the switch.

Thanks for pointing me to the Haynes manual. I've checked the black wiring from the key switch to the light switch and all appears in place.

I checked volts on each terminal of the light switch. When switch is off I get around 4-5 volts on only the two black wires. When pulled out fully I get around 3-5 volts on all 5 terminals.

I noticed some heavy rust/corrosion on terminal 30 and 58 on the light switch. So plan is to take the switch out later tonight and clean up the terminals properly.

Thanks for your advice so far... I beginning to enjoy this detective work... I might end up checking out all the electrics.

[Derek UK]

Without wanting to get too mixed up in this, just a few thoughts. The light switch is pretty reliable and if as you say they rheostat is working well that's a plus too. The foot dip switch can be cranky and best checked off the car especially if its had to cope with water flowing down the bulkhead. Although you say you've redone the fuse box, at least remove the fuses and check them carefully. Clean up the contacts and don't put any "paste" on them for now. Just behind the nearside headlamp the wiring loom has a black block connector for the front lights. This is probably the junction box you mention. Pull this apart and check/clean all of the pins and sockets. Make sure none of them get pushed back as you push the two halves together.

First test - put your headlights on and roll the fuses. Start with the bottom one. You might just fix it in 5 seconds. If by yourself, easier to see when it's a bit dark.

[jpws]

Hi Derek, thanks for chipping in, much appreciated. I had the footswitch out on Saturday and checked it and it worked fine, despite having been in damp conditions for a bit. I also now removed all fuses and put them back in (without any paste). No improvement.
I will check the junction box next.

Tonight I also removed the main lightswitch from under the dash. The 56 terminal and clip were badly corroded. Very helpful diagram can be found here http://www.volvoforums.org.uk/showthread.php?t=100943
I spent the evening cleaning the terminals on the switch and measured resistance across 30 (power input), 58 (parking light output), and when fully on 56 (headlight output). 30-58 works no problem, 30-56 is intermittent depending on rotation/position of the switch for the instrument lighting. When instrument lighting is fully turned up then the resistance is low and I get a connection, then when turning the instrument lighting down the connection gets interrupted.
58a - 58b appears to be connected all the time.

More powder falling out of the switch, so likely something wrong inside. Also when driving today with parking lights on the main lightswitch got rather warm. Not sure if that's normal or indicates some resistance problem? Maybe it's time for a new light switch??

Will put the switch back in tomorrow in daylight and see if my cleaning had any effect. I think I will also replace the female connector on the headlight output wire, which is corroded.

More tomorrow...

[volvogv]

Let me zero in on something if I may. You mentioned that you are reading 5 volts on your meter. Let's do a sanity check to be sure this is correct. First, are you using a digital meter or one with a dial scale? The dial meters can be confusing to read. I'm going to assume you are using a dial or analog meter. My meter has a switch setting for 5VDC, 25VDC, 125VDC, 500VDC. Since a car runs on a DC battery we have to use the DC scale, not AC. Then you know that you are expective 12 volts so you select the correct "range". In this case 5VDC is too low because the incoming voltage is higher. 25VDC is correct because it's the first setting that is higher than the voltage being read. Next, look at the meter scale's right side. You'll see numbers stacked on top of each other. In my case I choose the number 25 to match the switch setting. When the needle touches the last mark, you are at "full scale" and you're reading 25 volts. Using that same set of numbers(example, third from top), follow it down the scale until you have your voltage. I just want to be sure you're reading your meter correctly. If this isn't clear, let me know and I'll post some pictures.

Just to get a baseline reading, put your meter across the battery terminals and you will see 12 volts unless it's dead.

Good find on the corroded terminals. That will cause electrics to stop working. The white powder that keeps falling out of your switch is pure corrosion. If it were me, I would replace it with a new one.

I tried to get you a part number for the headlight switch but I'm having trouble reading the online parts manual. Derek probably has the number in a book somewhere?

[jpws]

Thanks for the advice on reading the meter. Although I live in good old England and like to keep things as original as possible, I do have a digital meter. So no needles and different scales unfortunately for me, but am tempted to look into that one day.
Just to be absolutely sure, I tested the meter on the battery, reading 12.56 volt.

This morning I replaced the female connector on the green/headlight wire, as the old one was heavily corroded and just about fell off when I touched it. Then used copper paste on the switch terminals and put it all back together. Bingo, lights are working again, both normal beam and high beam. When adjusting the instrument brightness (turning the knob), the headlights come and go briefly, but appear to be working ok.
Also took the black 6 point connector apart inside the nearside/left wing, gunky on outside, looks fine inside.
Will test drive the lights properly in the dark tonight.

If anyone has a working spare or knows where to get a new/replacement light switch (it's part no. 663748-2 European version, 673223-4 for USA/CAN version), please let me know. Brookhouse hasn't listed it on their website and Skandix says it's discontinued. Will give Simon a ring.

Thanks very much volvogv for guiding me through this and showing me that the Amazon electrics are not that difficult as long as you know what you are doing or has someone kind like yourself to "hold my hand". Very much appreciated. Thanks Derek for suggestions too.

I am always amazed by and thankful for the many helpful and knowledgeable people on here!

[Tail]

I would look on e-bay for a secondhand light switch, there are a few sellers with Amazon bits on there who may not have listed a switch but who do have one knocking about, just send them a message and ask.