Technical Headlight gremlins

[hugh w]

Hi all.

I currently don't seem to have any dipped beam working, but this is since I was fiddling with something else...

(Background) The speedo illumination hasn't worked since I bought Rosie (500F). So once I found out how to remove bulb I tested it (OK) and got my test probe on the switch for it (Also OK). The bulb doesn't seem to locate properly in the bayonet holder though, so could be this or the earthing of this holder into the speedo housing?

Back to the headlights problem...sometime after the above investigation I realised that a fuse had blown (5th down, which covers indicators, instr lighting and brake lights) Therefore seems reasonable that it blew when I was investigating speedo bulb.
Replaced fuse but then noticed that headlights weren't working properly. I thought initially I had no main beam but I think its actually no dipped beam (newbie, how can I tell with no frame of reference, and only 5W difference in brightness?)

So checked all fuses (OK) checked both bulbs (OK) checked headlamp bulb holders (Only voltage is to one of the 3 contacts, I know black wire is earth, so its the 'top' connector which has no power (Grey wire) which I presume is therefore low beam? So presumably the issue is upstream of that connector.

I'm not really sure what else to check. Could be column switchgear but I can't workout how to get this off. There's a small cream collar which Ive taken the screw out of but that still doesn't reveal all the wiring connections. Do I need to remove steering wheel? I presume if I can access the grey/black wire or terminal near here, that will show me where the voltage "disappears"?

I'm sure it could be a bad earth somewhere but where to start?

any pointers appreciated


cheers

Hugh & Rosie


P.S When removing speedo bulb I must have dislodged a bullet connector (see picture) since its a grey wire connecting to grey/red I'm presuming this is the low beam supply and therefore part of the issue?)

 

[MalcolmfromMoffat]

Most times I’ve had headlight gremlins it been an earth at fault, as you say the black wire on our 500’s If I remember correctly bolted to the vehicle on the fixings holding the side lights which aren’t just ideal for making earth especially if recently painted bodywork. I also had some issues with the fuse box which appeared perfect and fuses fine but sometimes a twiddle of the fuses in their location was needed to make connections. My apologies for the vagueness, I’m hugely hindered with electrical matters, just not my area at all but these are simple enough where even I usually manage to track the fault down.

 

[hugh w]

Most times I’ve had headlight gremlins it been an earth at fault, as you say the black wire on our 500’s If I remember correctly bolted to the vehicle on the fixings holding the side lights which aren’t just ideal for making earth especially if recently painted bodywork. I also had some issues with the fuse box which appeared perfect and fuses fine but sometimes a twiddle of the fuses in their location was needed to make connections. My apologies for the vagueness, I’m hugely hindered with electrical matters, just not my area at all but these are simple enough where even I usually manage to track the fault down.

Thanks Malcolm, I guess I just need to do some more wiggling! I think the fusebox is probably a good shout. As you say it looks fine, but I'll clean all the contacts etc.
Im slightly confused about the dash mounted lights toggle switch... the middle position doesnt seem to do anything?
cheers
Hugh

 

[fiat500]

Thanks Malcolm, I guess I just need to do some more wiggling! I think the fusebox is probably a good shout. As you say it looks fine, but I'll clean all the contacts etc.
Im slightly confused about the dash mounted lights toggle switch... the middle position doesnt seem to do anything?
cheers
Hugh

Hugh, do you mean, the middle switch does nothing, or does the master light switch have three positions? I thought that all three toggles were either on or off.
The lights can be mysterious.
I think you can eliminate a bad earth since you still have one of the headlight beam options on both sides; the double filament bulbs share the earth.
On the wiiring diagram that I can most easily read, the the headlight feeds originate from the ignition switch to the fusebox, where they are effectively shared circuits via paired fuses. I agree as above; the most likely culprit is either one of those two fuses or the spade connections either side of them. So, judicious cleaning of terminals, with electrical contact grease applied before reconnection, is the cheapest and least complex potential solution to try first.

 

[hugh w]

OK thanks I'll try that. Yes the dash toggle switch for the lights has 3 positions, is that not the norm? Perhaps somebody has changed the switch at some time, for a non-standard one if thats the case

 

[fiat500]

OK thanks I'll try that. Yes the dash toggle switch for the lights has 3 positions, is that not the norm? Perhaps somebody has changed the switch at some time, for a non-standard one if thats the case

The originals are on/off.
It's probable that there has been some simple modification to the wiring, but the switch may still be operating as original.
Removing the column mechanism is a pain, and unlikely to be the issue. But checking the condition and connection of the bundle of bullet connectors under the bonnet, that connect it to all of the lighting circuits might find a simple fix.

 

[shera2025]

Since voltage isn’t reaching the low beam, the problem is likely the switch or wiring/earth. You can usually access the stalk without removing the wheel. Trace the grey/black wire from the switch to the headlight to see where power stops.

 

[fiat500]

That three way switch might be a clue. Perhaps there has been a previous issue with the stalk, and it's rewired to work low/main beam from the dash switch instead. I would look behin.... maybe remove it, and see what's going on.

 

[hugh w]

That three way switch might be a clue. Perhaps there has been a previous issue with the stalk, and it's rewired to work low/main beam from the dash switch instead. I would look behin.... maybe remove it, and see what's going on.

I will, but the lights did work “normally” until recently. I’m sure I’ve upset something somewhere

Since voltage isn’t reaching the low beam, the problem is likely the switch or wiring/earth. You can usually access the stalk without removing the wheel. Trace the grey/black wire from the switch to the headlight to see where power stops.

Thanks, yes that’s my next investigation

The originals are on/off.
It's probable that there has been some simple modification to the wiring, but the switch may still be operating as original.
Removing the column mechanism is a pain, and unlikely to be the issue. But checking the condition and connection of the bundle of bullet connectors under the bonnet, that connect it to all of the lighting circuits might find a simple fix.

I just wish you didnt have to be a contortionist!

 

[hugh w]

So its fixed...just about. I'm not entirely sure how, as once I solved the headlight problem I suddenly had another rear light problem and lost high beam on one side! Still its sorted now except for LH rear light is brake light intensity when on, but I can live with that for the moment as don't intend to drive at night.

 

[MalcolmfromMoffat]

Thats very much the symptoms I had when the fuse box wasn’t playing ball, there was nothing wrong with it but just wasn’t making the connections consistently. With a bit of reseating of fuses and connections it has been trouble free since.

 

[hugh w]

Thats very much the symptoms I had when the fuse box wasn’t playing ball, there was nothing wrong with it but just wasn’t making the connections consistently. With a bit of reseating of fuses and connections it has been trouble free since.

Yes it feels like just going over a bump might dislodge a fuse, unlike the cylindrical ceramic fuses in other older cars that locate much more positively. Explains why the previous owner had put rubber bands around one of the fuse ways!

 

[fiat500]

It's good that it's working again.
You may have that rear lamp fitted in its holder 180 degrees out. Or the spades on the light fitting terminals need switching round.

 

[hugh w]

It's good that it's working again.
You may have that rear lamp fitted in its holder 180 degrees out. Or the spades on the light fitting terminals need switching round.

Who knew? Well actually you did, I hadn't realised that bulb orientation mattered for 2 filament oners
Cheers Peter!