Think I need a new fusebox...

Experiencing several intermitant electrical problems. Pretty sure all earths are ok but here are the symptoms. Car is an 81 1600gti hitw he early bullet style fusebox.

Fuel pump sometimes primes, sometimes doesn't when turning ignition on. When changing from main beam to dipped beam, fuel pump primes sometimes. When putting indicators on (when they are working) fuel pump might prime twice then stop - sometimes. No indicators but green light lights and stays on but is also dimly light when ignition on and indicators off (possible relay?) - sometimes! Hazards are ok. No spark from coil - sometimes! Got to be the fusebox right?

Is it a real pig to 'upgrade' to the later style (blade) fusebox and why is the early style one almost twice the cost of the later style one at GSF?!

Got to be the fusebox right?

Are you sure you have 100% been over all the earth points  :dontknow: Earths are the best source of intermittant problems . Mind you so are wet and corroded fuze boards .

Why not drop the fuze board down and inspect it for corrosion , seems to me to be lots of minor things not one major one . Tackle each part in turn and see if it leads you to a common point , if you follow my drift  

Cheers chudd. Fusebox was a bit messy so have ordered a new one from gsf. Should have bought shares in them the amount I've put their way recently! See if that solves any problems. If not then it looks like a new indicator relay for starters. Had all earths disconnected and sanded then greased - under dash (star pronged thingy), rocker cover to coil bolt, gearbox to chassis, one in boot. Not found any others…

just put a new bullet fuse box in my gti that i bought from scouse on here (is there anything he hasnt got) and it sorted all my electrical gremlins. alot cheaper than gsf aswell!

Damn. Have already ordered mine. Will have to remember to try scouse or crazy first next time... Should be here tomorrow so we will see...

Ok, so a new fusebox hasn't solved anything, neither has a new indicator relay. Cleaned all fuses that went back into the new fusebox.

Still have the dash indicator light semi lit when ignition on and permanently lit when putting indicator switch on but no flashing and no lit indicators. Hazards work as they should so that rules out bulbs and possibly wiring from the fusebox?

No spark at the coil still. Going to try a replacement coil and dizzy after the weekend.

Am pretty sure it has to be a wiring problem somewhere at the back of the fuse box but everything looks ok to me. Pretty sure the two problems are related too as both happened at the same time, cured themselves at the same time and then failed again at the same time (and haven't decided to cure themselves again!)

Anyone got any ideas? Looks like it's out with the multimeter and the haynes wiring diagram again. Great! Took me 3 hours to find a split wire for the dipped beam. God knows how long this will take!

Does sound like earthing problems, this is a list of most of the earthing points posted by Dubboy a while ago…

Rosette LH side behind headlamp (LH lights, front washer)
Rosette RH side behind headlamp (RH lights)
Strap from alternator to engine block
Strap to rocker cover (82> models only?)
Earth wire from diagnostic terminal block to battery (>76 models only)
Earth cable from battery to body
Earth strap gearbox LH mount to body
Earth wire from steering rack bracket to body (for horn)
Rosette on back of instrument panel
Rosette on bulkhead near fuse box / steering column bracket
LH front door contact switch (self earthing)
RH front door contact switch (self earthing)
LH rear door contact switch (self earthing, 4-door models)
RH rear door contact switch (self earthing, 4-door models)
Earth wire to interior light bracket
Earth wires to body floor (under rear carpet near bench seat for fuel pump and fuel tank sender)
Earth wire near LH tailgate hinge behind headlining (rear wiper motor)
Earth wire near RH tailgate hinge behind headlining (heated rear window)
Earth wire to rear tailgate slam panel LH side (LH rear lights, number plate lights)
Earth wire to rear tailgate slam panel RH side (RH rear lights, rear washer)

Cheers

woZa said

Hazards work as they should so that rules out bulbs and possibly wiring from the fusebox?

Your problem might be the switch itself.

While dismantling my dashboard I accidentally opened up the hazard switch, and bits went everywhere. I put it back, but minus 2 little springs (which I found later) - I had exactly the same symptoms as you, although my hazards didn't work either.

The springs keep the 2 contacts in the switch in contact with the back of the switch assembly, and help make a good circuit when the switch is off or on. You may be missing one or maybe even both of these… Once I'd reassembled the switch properly, the dim green light disappeared, and everything worked as normal.

Worth a look anyway, and much easier than that bloody Haynes manual malarkey  8O

Cheers mcsrew. I'll look into that. Seemed to happen at the same time as the no spark issue though. I have a feeling it is a wiring problem somewhere though…

easy way to check if its the switch is to dissconnect it, if the light for indicators is still on you can rule that out!

tupac2makaveli71 said

easy way to check if its the switch is to dissconnect it, if the light for indicators is still on you can rule that out!

This caught me out actually - if you disconnect the switch then nothing will work at all (i.e. no indicators / dash lights / etc)…

its almost like everything has been wires in series  8O

I have now rewired the engine bay ignition side of things… From the TCI switch to the coil, hall sender and battery and the car still won't start. Further checks revealed that the coil is only getting 1.2v when the ignition is switched on rather than the 12v it should be getting. So I figured I would give the coil 12v direct from the battery (only temporarily) to see if that would help. Turn the ignition on and the indicator dash lamp is no longer lit. Try the indicators and the indicator relay (a new one) buzzes like a mad thing! Try to start the car and still no luck.

What could be causing the low voltage at the coil and why when feeding the coil 12v direct does the indicator dash lamp go out??? :dontknow: I' getting very confused now!

You may have shorted something out when you connected the coil direct to the battery. While I was trying to get my horn to work, I put 12v from the fusebox onto the contact on the steering column, and the oil temperature guage started showing 90?C 8O

Your problem could be earth related, as it's hard to see what else it could be if you've already replaced the coil, the wiring, the fusebox, and cleaned the fuses. Do you have a constant 0v on the negative side of the coil?

mcscrew said

Do you have a constant 0v on the negative side of the coil?

No… getting the same as on the positive side of the coil, 1.2v (or 12v when giving it a feed from the battery). Have replaced the wires to the coil from the fusebox, still no change. The only difference after all the rewiring is that the dim dash indicator light doesn't go out when feeding the coil 12v direct from the battery and the alternator light stays lit now when the ignition is on.

When the ignition is on the wires from the fusebox to the coil give 3.4v (red/black c19 +ve) and 4.1v (black c15 -ve). Surely this can't be right? (Both are 0v when igntion off)

Hmmm! That definitely doesn't sound good.

What voltage do you get if you remove all the wiring from the coil, put 12v direct from the battery to the positive side, and the voltmeter between the negative side and the negative battery terminal? It should be 0v, as no current should flow through the coil when it's disconnected from the engine.

If you get 12v on the negative side too, then the coil is shot, and if you get 0v on the negative side, then the wiring is incorrect (I think).

To test this, measure the voltage between the negative wire for the coil, and the negative terminal for the battery. You should get a constant 0v - if so it's the supply wiring which is faulty, and if not it's the earth wiring which is wrong.

HTH

Rich

mcscrew said

Hmmm! That definitely doesn't sound good.

What voltage do you get if you remove all the wiring from the coil, put 12v direct from the battery to the positive side, and the voltmeter between the negative side and the negative battery terminal? It should be 0v, as no current should flow through the coil when it's disconnected from the engine.

If you get 12v on the negative side too, then the coil is shot, and if you get 0v on the negative side, then the wiring is incorrect (I think).

Cheers for the help Rich. Are you sure that there should be 0v on the low tension side? It's just that all 3 of the coils (2 old & 1 new) show 12v when doing the above but I find it hard to beleive that all 3 have gone in the same way…? The resitance is within limits on all 3 of them on both the LT & HT. I'm more concerned that the wires supplying the coil are giving only 3v or 4v. One of them should be 12v surely? Both wires come directly from the fusebox (which is new) and are new wires too…

Hmmm - electrics do confuse me considerably  

If they all show 12v on both sides under those test conditions then I reckon you're right - all the coils are working correctly, and you should be more concerned with the voltage supply. Like you say, one side of the coil (at least) should be 12v.

At this point I'm as confused as you are - new wires and a new fusebox doesn't leave much room for error anywhere  :? Unless you get 12v at the fusebox, and 4ish at the coil?

Beyond this I'm stumped I'm afraid…

Rich

I put an additional earth point on the n/s and o/s rear indicator using the spades visible on the back of the cluster, both indicators are now earthed and the indicator light on the dash doesnt glow. give it a shot but watch for the live spades in the cluster.