Weird lighting issue.

[FirstSpider]

Hey guys, I'm a=happy to report that thanks to all of your wonderful help my Spider is back on the road! However, unfortunately I have discovered a new issue (of course). When the headlights are in high beam only one side works, when in low beam only the other side works. I have not Brake lights, turns or tails. My hazards do work though. What could this be? where should I look? What should I replace? Thanks in advance.

[So Cal Mark]

start with the fuses

[FirstSpider]

Thanks, I already tried them though. Replaced them all a few weeks ago. No dice.

[aj81spider]

Amplifying on what Mark said. Each headlight is powered from a separate fuse for both high and low beams (4 fuses total). If one headlight is working and the other isn't then the place to start is whether power is getting to them. You can measure at the fuse box to see if power is coming through the fuse. If it is then you can trace the connectors and see where the connection is broken. If it isn't then you probably have a fuse box problem.

[blurple124]

It would almost seem as though your tail light issues are unrelated to your headlight issues. If the headlights are working, it means that your column switch is getting power, but it isn't getting all the way to both fuses. Those connections can come loose, so keep an eye on it.

As for the tail lights, start by checking the lighting switch. Perhaps a connection is loose there.

[majicwrench]

Start at the headlight connectors, check for power!!! Could very simply be that you have bad headlights. If they don'
t have power, then check fuses. Replacing fuses is not checking them. Need to check for power on both sides of fuse, at the TERMINAL in the fusebox and not the fuse itself. Learn to use a test light, tis the finest electrical test tool you can have.
' Keith

[FirstSpider]

Ok, So I got the headlights and tail lights working, but no luck with the turns.

[blurple124]

Do any of your T.S. work? If not, look for power getting to your flasher relay first. And make sure it has a good ground.

[profcucchi]

Start at the headlight connectors, check for power!!! Could very simply be that you have bad headlights. If they don'
t have power, then check fuses. Replacing fuses is not checking them. Need to check for power on both sides of fuse, at the TERMINAL in the fusebox and not the fuse itself. Learn to use a test light, tis the finest electrical test tool you can have.
' Keith

This is probably my issue with my headlamps.

I have a testlight and multimeter.

Testlight:
The alligator clamp goes on metal and the metal rod goes into ?

Multimeter:
The black rod goes onto metal and the red one goes into?

Thanks.

[aj81spider]

Test light and multimeter behave generally the same way with the test light simply lighting up when there is voltage and the meter giving you a reading for the value of the voltage. Here's the multi-meter overview:

> Get a wiring diagram. You can't trace circuits without it. If you don't have one PM me with your email and the year of your car and I'll send you one. I have most years.

> I'd start with the fuse box. Not because I disagree with Kieth (who knows lots more than me) but simply because you don't have to disconnect anything to get to it.

> Set the meter to measure DC Volts at the smallest scale that is greater than 12 V (usually something like 0-20). With the lights on - Black probe on metal, use the red probe to check both sides of the fuse - touching the connector with the probe (be careful and don't short fuses together with the probe!). In a working car you will get 12 V on both sides of the fuse. Check the two fuses that power the low beams and the two fuses that power the high beams with the switch in the appropriate position. If there is power on one side of the fuse but not the other then the fuse is either blown or not seated correctly. If there is no power then you need to trace the circuit back toward the switch - I'd check at the switch next. If there is power then move to the lights.

> When checking the lights, remove the headlight. There is a 3 position connector it is plugged in to. One position goes to ground, one is low beam and one is high. Check the voltage on all 3. The ground should read 0 volts. You should get 12 volts at each of the others when the headlight switch is in the appropriate position (and 0 when it is not in the appropriate position). If there is no power at the connector, but there is power at the fuse then you need to trace the wiring and find the break. If there is power at the connector, but the light is not lighting then you either have a bad headlight or you have a bad ground.

The circuit is not that complicated and by tracing the voltage through it you will eventually find the problem. It can only be one of a few things: Bad switch, bad bulb, blown fuse, cut wire, bad ground.

If you have no electrical experience think of the wiring diagram as a set of pipes flowing water instead of electricity. The voltage you are measuring is equivalent to water pressure and the current is equivalent to volume of water flowing (and like water, the higher the pressure/voltage the more electricity that flows). You are simply trying to trace the flow via the diagram and make sure there is adequate pressure everywhere in the circuit.

Good luck!

[profcucchi]

Test light and multimeter behave generally the same way with the test light simply lighting up when there is voltage and the meter giving you a reading for the value of the voltage. Here's the multi-meter overview:

> Get a wiring diagram. You can't trace circuits without it. If you don't have one PM me with your email and the year of your car and I'll send you one. I have most years.

> I'd start with the fuse box. Not because I disagree with Kieth (who knows lots more than me) but simply because you don't have to disconnect anything to get to it.

> Set the meter to measure DC Volts at the smallest scale that is greater than 12 V (usually something like 0-20). With the lights on - Black probe on metal, use the red probe to check both sides of the fuse - touching the connector with the probe (be careful and don't short fuses together with the probe!). In a working car you will get 12 V on both sides of the fuse. Check the two fuses that power the low beams and the two fuses that power the high beams with the switch in the appropriate position. If there is power on one side of the fuse but not the other then the fuse is either blown or not seated correctly. If there is no power then you need to trace the circuit back toward the switch - I'd check at the switch next. If there is power then move to the lights.

> When checking the lights, remove the headlight. There is a 3 position connector it is plugged in to. One position goes to ground, one is low beam and one is high. Check the voltage on all 3. The ground should read 0 volts. You should get 12 volts at each of the others when the headlight switch is in the appropriate position (and 0 when it is not in the appropriate position). If there is no power at the connector, but there is power at the fuse then you need to trace the wiring and find the break. If there is power at the connector, but the light is not lighting then you either have a bad headlight or you have a bad ground.

The circuit is not that complicated and by tracing the voltage through it you will eventually find the problem. It can only be one of a few things: Bad switch, bad bulb, blown fuse, cut wire, bad ground.

If you have no electrical experience think of the wiring diagram as a set of pipes flowing water instead of electricity. The voltage you are measuring is equivalent to water pressure and the current is equivalent to volume of water flowing (and like water, the higher the pressure/voltage the more electricity that flows). You are simply trying to trace the flow via the diagram and make sure there is adequate pressure everywhere in the circuit.

Good luck!

Thank you very much. I've tried to make sense of YouTube videos and wiki-everything, but this makes much more sense. And, I have the Artigue wiring diagrams, but no magnifying glasses!

[profcucchi]

Argh... I only have three fuses that show power: A, I and L.

Now the fun begins?

Or is this an ignition switch problem? Potential costs?

[aj81spider]

A couple of questions:

> What year is your car?

> Was the car running when you checked the fuses? Those fuses sound suspiciously like ones that have power all the time (i.e. when the car is off). To check the headlight fuses the car needs to be running and the lights need to be on. On an 81 the fuses are C and D for low beams and E and F for high beams.

If the car was running then you have a lot more that's not working than the lights!

[profcucchi]

I went to a local Fiat mechanic who took one look at the rats nest of wires and realised that the PO, or one of them, made changes that drew power.

He made a quick fix, and we'll leave it for another day to do it by the book.

I now have lights and can cruise at night, again.