Electrics - New Problem!!!

[niklee1]

Hi all can anyone give me a but of advice please?
Got in the bus today and it started ok but I have no lights on the dash or indicators, though windscreen wipers work ok! Runs fine and battery getting charged.
Thanks in advance.

 

[gvee]

Check fuses and relays.

 

[Kaboosie]

May be a bad earth wire somewhere. Just finished sorting out wiring on my bus, loads of bodge ups people have done over the years, wires twisted together etc. Found this site very helpful speedyjim.net.

 

[niklee1]

Ok thanks guys I'll have a look.

 

[starbiscuit]

When you say "no lights on dash", is that really all of them?
(backlight, indicator repeaters, oil pressure, hi-beam, battery charging etc.)
And what about fuel guage?

Headlamps / side-lamps?
Hazards?

Which ones do or don't work will help narrow down which circuit(s) are faulty.

 

[niklee1]

All dash lights main beam indicators gen and batt. Fuel gauge doesn't work but that never has.
Not sure on illumination lights until I get home tonight. Dipped and side lights work ok. But indicators do not.

 

[starbiscuit]

The indicator repeaters in the dash, battery charge warning, oil pressure warning and fuel gauge all come off the same ignition fuse on my 1970 bus (fuse #4 I think)
That same fuse also supplies the indicators themselves.

It doesn't supply the main beam warning lamp or the dim/dip headlights or side lights, so that might be a separate issue.

Also it doesn't supply the hazards, because they should work with ignition off, so that might be a way to confirm the flasher relay and indicator lights themselves are working.
And if the hazards are not working, it's possible that there's a short in one of the indicators themselves, or the run to it, or the flasher relay. That should blow a fuse.

The battery feed for the hazards comes off fuse #1 or 2 (I think) that also runs the dim/dip headlamps and the interior light.

Only ten of the fuses are used in my 1970 bus, so it's fairly easy to narrow down which one is gone by what else works.
Or pull them one at a time and inspect / test them.
Note that they do work loose, or corrode, or fail from old age.

But if a fuse has failed because the wire has melted, it would be sensible to try to locate the root cause otherwise the replacement fuse will likely go the same way.

HTH.

 

[niklee1]

Hi all found the cause, the fuse cover fell off and the metal glove box strap had shorted the fuse!!! I found this out when I was removing it to gain access to the fusebox :shock:

Anyway thanks for all your comments....however I have another query. My headlight flash and main beam has not been working lately...well a while :msn4: but I noticed tonight that it works fine when the ignition is switched off!?!? But as you turn the key it stops working!!!

Any ideas???

 

[starbiscuit]

Have you another dim/dip relay you could try to rule it out?
The relay is operated by grounding the brown/white wire through the pull switch on the steering column.
So you could disconnect that wire at a convenient connector near the steering column and ground it to see if the relay operates, with ignition off and on.
It could be that the brown ground wire (31) to the steering column switch isn't grounded properly. I don't know where it goes on yours, but on mine it daisy-chains to the light switch, the hazard switch and ends up on a stud on the back of the instrument cluster.
It might pass enough current through a bulb or some other circuit when ignition is off, but with ignition ON, it's not a low enough voltage to operate the relay.

Again, just guessing.

Do you have a voltmeter you can poke around with?

 

[niklee1]

No I don't have another relay, but I do have a voltmeter. Could it be something like two wires crossed?

 

[starbiscuit]

Could be anything really, depending whether something was changed or work done to the bus that caused the fault, or whether a part of the circuit (relay, connection) failed all by itself.

It's well worth downloading the wiring diagram for your year bus and tracing it through.

You could measure the voltage between a good ground and the connection of the brown/white wire to the relay.
You would expect it to be 12V until you pull the stalk switch, when it should go to 0V (ish).

If that connection doesn't go below 3V, especially if it is different with ignition on, that might not be low enough to operate the relay.

Pushing a spare bit of wire into that brown/white connection and connecting it to ground should operate the relay and that should tell if the fault is in the relay itself or in the stalk circuit.

It is also possible that there's a poor connection in the circuit to the + side of the relay coil (loose or corroded fuse?), such that when you turn on the ignition there is a big enough volt drop in the supply to the relay that it can't operate.

 

[niklee1]

Thanks I'll check that out and let you know...

 

[niklee1]

Could be anything really, depending whether something was changed or work done to the bus that caused the fault, or whether a part of the circuit (relay, connection) failed all by itself.

It's well worth downloading the wiring diagram for your year bus and tracing it through.

You could measure the voltage between a good ground and the connection of the brown/white wire to the relay.
You would expect it to be 12V until you pull the stalk switch, when it should go to 0V (ish).

If that connection doesn't go below 3V, especially if it is different with ignition on, that might not be low enough to operate the relay.

Pushing a spare bit of wire into that brown/white connection and connecting it to ground should operate the relay and that should tell if the fault is in the relay itself or in the stalk circuit.

It is also possible that there's a poor connection in the circuit to the + side of the relay coil (loose or corroded fuse?), such that when you turn on the ignition there is a big enough volt drop in the supply to the relay that it can't operate.

Hi mate when connecting the ground to earth the relay operates ok. So is that a fault with the stalk? Is so is it fixable? Or replacement?

 

[starbiscuit]

Did you try it with ignition on and off?

If so, I think that means the fault must be in the brown/white wire through to the switch, or the switch itself, or the brown wire through to ground.

If you remove the dim/dim relay (so there's no current in the stalk circuit) and measure the resistance across the stalk switch (at the connector: between brown and brown/white wires) - it should be open circuit until you operate it, when the resistance should read only a few ohms.
If it's more than a few tens of ohms, that might be your issue.
It is possible to clean the contacts with a switch cleaner, like isopropyl alcohol (Maplins sell it in an aerosol), or very gently with fine emery.

If the switch resistance is only a few ohms, the issue is more likely the connection to ground from the switch. You can measure the resistance to a good ground from the switch (brown wire at the stalk connector). It should be almost zero ohms (single figure ohms maximum).
If not, you could trace where the brown wire goes and try to address whatever dodgy connection you find, or run a new brown wire to a good ground from the stalk switch connector.

Replacing the switch is possible, but hopefully not necessary.

HTH,
Rob

 

[niklee1]

Update: I have checked the relay. When I run a good earth to the terminal on the stalk it activates the main/dipped with lights on and headlamp flash with no lights, so its not the relay! The stalk does not 'click' or activate any lights, (it was loose last week when I first posted the problem now its firm which leads me to deduce that something is wrong with the stalk, I have cleaned the stalk with alcohol cleaner.

 

[starbiscuit]

If you tested a good ground to the brown/white wire connection at the stalk, you are bypassing both the stalk and the normal ground connection, so it could be either of those at fault.

If you connect a good ground to the ground side of the stalk (brown wire connection), then the stalk is the only variable you are testing. If the relay works in this test, the problem is with a dodgy ground connection.

 

[niklee1]

If you tested a good ground to the brown/white wire connection at the stalk, you are bypassing both the stalk and the normal ground connection, so it could be either of those at fault.

If you connect a good ground to the ground side of the stalk (brown wire connection), then the stalk is the only variable you are testing. If the relay works in this test, the problem is with a dodgy ground connection.

Ok, I'll try that over the weekend, I'm really getting this electrical testing thing now . Thanks I really appreciate your help.

Nik