Intermittent headlight failure on T350t

[petrolburners]

Hi there,

I was driving along last night at circa 11pm on an unlit dual carriageway at somewhere above 69mph and all of a sudden my dipped beams completely failed. A couple seconds pass before I reach for the main beams which thankfully illuminate and come to the rescue...

Pull over, turn off, turn on, repeat several times and eventually the dipped beams jump back to life.

Any thoughts?

Can't imagine its fusing as a fuse either allows current to pass or is blown... there shouldn't be any intermittency. Perhaps a relay? Perhaps something else?

Please advise, thanks!

[Let off some steam Bennett]

My drivers side front indicator was doing this on my tuscan, it turned out to be furry green connections in the plug from the loom to the indicator loom. Cleaned them up and no problem now

[non_linear]

Hi
I have a similar problem so am interested in any solution you find.

I've just bought a T350T and found out while driving it home that the dipped beam didn't work. Had to grit my teeth and drive on full beam for the last half hour.

Does anyone know where to get hold of a wiring diagram for the T350?

cheers
Stuart

[RAS]

The Graham Varley manual is very useful, but they are as rare as hens teeth.
You might find the online section helpful, under Electrics Fault Finding, it mentions flickering head lights: http://www.varleyhyd.com/FJ062.asp#Front Lights

[non_linear]

Thanks, I'll have a look at it.

How similar are the T350, Sagaris and Tamora electrically? You would imagine they were virtually identical.

[Willfin]

I have the wiring diagrams on pdf if you pm me your email.

[NBON]

I have these issues on occasions. Check the ribbon cables behind the dash that go into the light control switch. And the pcb board where the other on of the ribbon cable goes.

Theres 2 bolts under the dash that need removing . Then the dash should slide forward enough to get access.

[non_linear]

Thanks Willfin, I've sent you a PM.

Hi NBON. Looking at the paperwork that came with the car I can see the dash ECU was recently repaired. I'm guessing that that is where the ribbon cables go, and is probably the place to start, followed by the dash. Very useful to know how to pull the dash forward, thanks!

[AndyT350]

I had this issue and it turned out to be dry/cracked solders on the PCB that the ribbon cables go to (i had issues with the dash LED's for the lights and air conditioning had a habit of flickering on and off as well) .. if wiggling the ribbon cables/PCB seems to resolve it could be the same problem. I've re-soldered and seems to holding up so far..

Andy

[jev]

I had a similar sounding issue on my Tamora. It was dry joints on the pcb exactly as AndyT350 says. Same solution, re-soldering.

[non_linear]

Thanks everyone!

I have an invoice from str8six showing another repair in 2014: "Inoperative headlights, traced to IDC Patch Panel and rectified".

IDC is another name for ribbon cable connector, so is the patch panel a board behind the dash, or do you think they mean the dash ECU to the right of the footwell?

[Yaaan]

Might be worth checking the light switch as well. Last year I had a similar problem but it must have been intermittent as it got through the MOT with Str8six ok and was certainly working when I got the car home. The issue manifest itself again at some point during the year and while it was with Neil Garner for MOT they replaced the switch and there have been no repeat problems so far.

[KillerJim]

It must be the weather, my dips are gone as well (they were intermittent last year but the winter has silenced them..)

In terms of the "best" order (i.e. avoiding complex work until really required) is it :

1) Look at dash cables (two screws..)
2) The relax splice box (a few screws? )
3) Dig way into bulbs to test bulbs and power going to bulbs ( wheel off, dig out silaflex from panel, open and inspect)
4) Go hunting for wires
5) Give up and get someone to look at it..

Anything I'm missing?

[NBON]

non_linear said:

Thanks Willfin, I've sent you a PM.

Hi NBON. Looking at the paperwork that came with the car I can see the dash ECU was recently repaired. I'm guessing that that is where the ribbon cables go, and is probably the place to start, followed by the dash. Very useful to know how to pull the dash forward, thanks!

As other posts. The pcb board is behind the dash and seperate from the ecu. Think i need to look at the soldering too.

[non_linear]

From what I am seeing here, and other threads, the possible culprits include:

Relays and fuses
The light switch itself
The IDC patch panel located behind the dash
The Relay/ Splice board located under the front of the centre console.
The dash ECU located to the right of the footwell. (My steering wheel buttons don't work either)

Then as Killerjim says, the bulbs and holders themselves.

Time to break out the multimeter and toolkit.

[petrolburners]

Thanks for the input everyone.

Non Linear, thank you for consolidating the possible problems so neatly... will work through them this weekend!

Failing that, it is booked for its service next month but I'd rather trace the issue myself.

Cheers.

[non_linear]

I've been looking at the wiring diagrams that Bob Honnor sent me and have tried to convert them into a circuit diagram, attached.
Firstly let me say, the circuit shown of the fuse box is a total guess, and could easily be wrong. BEWARE!
The wiring diagram makes no mention of the IDC patch panel, so it's not included.

My first thoughts are:
The OFF/SIDE/MAIN dash switch sends 12V to the RAS board, which sends 12V to the control stalk, which then energises the relays on the relay panel as selected.
The RAS board also connects to the DASH ECU, which controls the dash backlight level.

This means (if correct) that if the main beam is working then the RAS board is probably ok,
I'm guessing the problem going to be the switch itself, the IDC board (not shown) or the relay/ fuses.

Hope this makes sense and helps. If anyone has more info I'd love to know.

[KillerJim]

Great diagram.. though I can't comment on it's accuracy

I'm planning on locating the problem tomorrow, will report what I find!

[non_linear]

Good luck!

Mine are now working. It turned out to be quite an easy fix, replacing the dipped beam relay. Looking inside reveals the problem:!

[Alpha Omega]

You probably will be checking all the relays by opening them up, it's well worth doing