Electrics: Unusual headlight issue

[RowersS40]

If there's anything specific you needed let me know!

[loely]

Do you have the "old" H4 headlights or the newer H7 double headlights ? My guess is the older type.
loely

[loely]

Rowers40,
If you have the H4 lamps at the top is the negetive, by you measurements left side (0v to the +) is high (or low beam) and at the right (+3,5v to +) there is the voltage to low making the lamp go dim ( 12v - 3.5v.= 8.5v to light up the bulb)You have troubles on the + side Batt,relay ,wire connectors fuse or a kind of this.
If you try positive wire connected at the batt and removig the fuse for the headlamps and touch the right side of your bulb it should shine bright as befor.If this is the case check the relay and fuses , in a short word everything from bat till lamp.There is a bad connection somewhere.Most likly relay problem (as they wrote befor).
Good hunting
Loely

[RowersS40]

Originally Posted by loely

Rowers40,
If you have the H4 lamps at the top is the negetive, by you measurements left side (0v to the +) is high (or low beam) and at the right (+3,5v to +) there is the voltage to low making the lamp go dim ( 12v - 3.5v.= 8.5v to light up the bulb)You have troubles on the + side Batt,relay ,wire connectors fuse or a kind of this.
If you try positive wire connected at the batt and removig the fuse for the headlamps and touch the right side of your bulb it should shine bright as befor.If this is the case check the relay and fuses , in a short word everything from bat till lamp.There is a bad connection somewhere.Most likly relay problem (as they wrote befor).
Good hunting
Loely

Thanks loely. Yes I do have the H4 lamps.

I'll try your idea when I can, might not be until next weekend, and also hunt for where the fault is.

I've just been sat for 45 minutes with the solar panel on as it wouldn't start in a car park - it couldn't give the final push to start the car, so I fear it's a symptom of a wider issue.

[loely]

When you lose power while driving you should look at the voltage you have on the batt (while driving) try at the cigaret lighter. While driving it should go up to around14 v or up .If not you have alternator problems or the connection to the + batt.You can not charge when the alternator does not "sens" the batt.
If it happens while the engine is not running ,the alternator can lose power true the regulator build in (you can not see it).

[RowersS40]

Originally Posted by loely

When you lose power while driving you should look at the voltage you have on the batt (while driving) try at the cigaret lighter. While driving it should go up to around14 v or up .If not you have alternator problems or the connection to the + batt.You can not charge when the alternator does not "sens" the batt.
If it happens while the engine is not running ,the alternator can lose power true the regulator build in (you can not see it).

Thanks, I'll give that a go next week during my commute - worth trying to work out if it is the alternator or the mysterious oil leak that causes the power loss.

[V40T4R]

Originally Posted by loely

When you lose power while driving you should look at the voltage you have on the batt (while driving) try at the cigaret lighter. While driving it should go up to around14 v or up .If not you have alternator problems or the connection to the + batt.You can not charge when the alternator does not "sens" the batt.
If it happens while the engine is not running ,the alternator can lose power true the regulator build in (you can not see it).

Or maybe the negative cable from battery to gearbox, see under battery tray.

[RowersS40]

Thanks everyone for the suggestions. I had some investigations done today by the AA after my car wouldn't start:

He traced the issue with the headlights to a relay somewhere.

After investigating the stalling issue he disconnected the battery to reset the control unit (suspecting that it needed to re-learn the voltage to keep the car idling) and now only the nearside light works, and is on with full brightness.

The starting issue has been traced back to a suspected fault on one of the coils. He also suggested this was the issue with the power loss whilst driving. This could also explain my lambda sensor and rich smell when the car is going.

Combined with a few other issues, it's looking like it might be too expensive to fix, unfortunately. Unless there are further pearls of wisdom here!

[loely]

Hi,
If it is a relay for the headlamps, it can probably be found in the CEM module,You can change it yourself, see topics about this.Costs only a few £
he starting thing can be a coil in the starter but to me it looks od to lose power by it as the starter is disconected by a relay when not used.Loosing power while driving ,to my knowledge,can only by not loading enough or some BIG electric user (you load at 60 or 70 amps ).That seems unlikely.Are you shure your batt is ok?Can you try a different one for a while.
Your lamda thing can be a result off the low voltage seems to me but that is not my thing.
loely

[RowersS40]

Hi all

Thanks for all the help and suggestions. Unfortunately, I've decided to buy a new car due to the large number of faults outside of those mentioned here, continuing problems and unreliability. I decided the cost of finding the faults (given my technical ability), and fixing them, outweighed the benefit.

It would probably make a great car for a new mechanic to learn on!

My new car is a Volvo but hopefully, won't need to come on here for advice for a while...!