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GT6 Troubleshooting! UPDATE


Bigfella70

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Evening folks,

Ive commenced work recommissioning my GT6 today which included carefully removing a spurious electric fan (wired live to battery minus any relay or inline fuse)!

My hazard lights were inoperative along with the oil pressure lamp (bulb tested  out ok and I earthed the sensor lead with no sign of lamp illumination).

Hence a couple of questions if you don't mind!

I removed the three fuses, cleaned the contacts, closed them up a little and refitted the fuses. I seem to have 2x 35 amp and 1x 15 amp which I think is wrong and all three should be 35amp fuses.

Unfortunately after the above work in the fuse box my side lamps, numbr plate lamp and instrument illumination are not working.

Im assuming an issue with the fuse connection but despite "wiggling" the fuse no joy so far in restoring my lights. Will have another look tomorrow but would welcome suggestions.

I had a similar issue with the fuel gauge packing up along with heated rear window and wipers. Removing and refitting the top fuse restored wipers and fuel gauge but not the heated rear window. The car does still start!

Also any pointers to troubleshoot the defective oil pressure lamp? I have a meter and lots of patience!

Lastly could anyone please help me identify the two units in the photo below, situated to the left of the battery. They look like a relay or flasher type unit to me.

An enjoyable day with a few minor snags to work through!!

 

IMG_3583.JPG

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With a mauve feed its more horn relay than overdrive,  and not a flasher unit , mauve being permanent live, not ignition controlled

Some have a inline fuse to protect the side lamps hidden away under the dash , not sure if gt6 has this.

Have you changed the oil  warning bulb.

The fuse box terminals do connect circuits using the fuse cap to transpose feeds between the two clips

Pete

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OK BF, 

Have you seen this? It's for USA GT6s but the colour is very useful. Also the fuses are miss named but go by the colours. The fuse box is a swine, the spigots holding the ends of the fuses are not physically joined together and are only electrically connected when the fuse is inserted. As they're not connected they have no spring and little grip so sometimes only 3 of the 4 connect leading to weird faults.

The heated rear window come directly off the ignition switch, no fuse!  Similarly part of the headlight circuit has no fuse and comes straight from the alternator to the headlamp switch, which can get quite hot due to all the amps going through it.

http://triumphspitfire.com/wiring.html

 

GT6MkIIIwiring.thumb.jpg.3f0a0af305297b9b1e85e297a950b004.jpg

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Thanks gents, I have got a copy of that wiring diagram printed out in the garage to try help! Interesting re the fuses mis named which I will take into account!

The oil lamp bulb I have tested on a 12v feed and its fine. Tried earthing the sender wire but no joy. So I guess the fault is with the wire from the sender to bulb or with the positive side feed to the bulb holder.

I think I'll try and get hold of some new fuses for good measure and replace the old ones. I guess it's a bit of trial and error with the contacts to try and get them all into play.....

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BF,

A lot of us have replaced the fuse box with a modern 10 blade job. Actually logistically quite easy to do. Physically there are 3 wires to the bottom of the red fuse, 3 to the purple fuse and 4 to the green fuse. Split each of these to a separate fuse and you got 10 fuses. Simples! There are a few threads on here about doing it. 

 

Doug

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Thanks Doug, I'll look into an upgrade for the mid term future. Will initially try and get everything back working with the factory set up (I've actually made things worse by removing fuses and cleaning contacts) ! 

Did notoce that the cap of the 15amp fuse was turning when handled which can't be good! First job will be to replace the three fuses then check all electrical items so I can list what is and isn't working then do some methodical checks to try tie down what's wrong.

When you mention the diagram has wrong naming of fuses please could you clarify if they are just mixed up positions or more complex. I'm assuming the diagrams are reliable . I have a Haynes and copy factory manual but the colour diagram is so simple to follow...

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And  rear lamps and the claw  bulb  fittings are another source of mix and match single and double filament fittings and some have 

Dedicated earth wire some have the claw and lamp  holder as earth  get these all in the wrong places mix up whether its earthed or not

Makes for dim  christmas tree effect plagues the whole side light flasher reverse all  having problems

So make sure the twin and single filaments  bulbs and holders are not swapped and all claws have an earth

Can be a nightmare 

Pete

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BF,

My car is a late mk3 and when I noticed the error I wondered if they'd changed the order of the fuses, or an apprentice had wired it or it was a Friday afternoon job, or they weren't bothered which was which. Haynes had it wrong as well.

Whatever, the bottom fuse (red) is my middle fuse, the top fuse (purple) my bottom and the middle fuse (green) my top. Confusing huh? 

Best thing would be to unscrew the fuse box, 4 self tappers, and discover which colour is going to which fuse. 

Doug

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Quite a productive day today, slow methodical progress!

Purchased some 35 amp fuses from nearest auto store (Halfords) and swapped the old 15 amp middle fuse (side lamps, number plate lamp and instrument lighting). Fortunately all back on line although I noticed the Halfords fuse caps are slightly slimmer than the previous item hence had to squeeze in the contacts further to snug the fuse in.

I then set about testing the oil pressure lamp circuit. Basically no live feed at the bulb holder.

There is a nest under the drivers side where someone in the past has hastily wired some circuits all in the same blue wire! 

E.g. I have a spurious blue wire from the solenoid terminal shared with the white / yellow coil feed wire running direct to the ignition switch terminal 3 shared with the white wires.  On the diagram this ignition terminal feeds off to the alternator and ignition warning lamp, oil pressure lamp circuit, and ballast resistor. Not sure what the purpose of this spurious wire is, will have to give it some thought but would welcome any suggestions!

Also a blue wire running to the brake lamp switch from as yet unknown origin. Additionally there are blue wires running to the door courtesy switches and I note a blue wire from the back of the rev counter leading off to the rear of the car. Not had chance to follow that one up and see where it leads yet!

When checking the rear lamps the now infamous blue cable has been put to use on the rear lamp clusters.

I guess at some stage someone has hastily bypassed a wiring fault.

Im currently identifying and labelling wires and trying to trace there routes and purpose.

Faults still present are as follows:

Defective reverse lamps

Defective horn 

Defective oil pressure gauge 

Indicators not flashing (but do lluminate solid)

Hoping to get a few hours in on Saturday, hints and tips welcome. I'm actually enjoying steadily tracing and sorting this out!!

Regards.

Dave.

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Jist one comment  the white yellow should be on the starter side of the solenoid , not mixed in as a permanent feed

Its suppposed to feed the coil when cranking, to by pass the ballasted ign feed to the coil

It may well have been removed or bypassed , 

Depends on evololution there can be a ceramic resistor near the coil or a ign wire in white and dull pink built in the harness tom feed the coil   

To add a ballasted 6v coil has 1.5 ohms on the blade terminals  a no ballast 12v has 3 ohms 

This wont help the reverse lamps  or other illuminating problems 

Pete

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What Pete said and he's already mention dodgy earths which can cause some of these problems.

You have mk3 I think so you have a ballast wire, so no use looking for a ballast resistor. 

Does the interior lamp work, this should come on when you open the door and is operated by the door switches. I just replaced both my switches as they were faulty. 

There is a reversing switch, but before you start digging in to get to it check the wiring to the lamps as said a lot of faults are down to defective earths. The indicators on solid can be the same, earths, but isolate it and put 12volts and earth on it, does it click at the correct speed?

There are two horns, unlikely to both be dead. Try a live wire from the battery to the horns. The horn push puts an earth on the horn relay, try an earth to the relay to see if it clicks. The horn push might be disconnected.

Do you mean oil pressure gauge or are you talking about  the oil pressure lamp? The lamp, ballast wire and heated rear window also come off the same ignition connection. Turn on the heated rear window, it might not work, not many of them do! But the warning light should come on regardless. If it doesn't I begin to suspect a fault with the ignition switch.

Doug

 

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Thanks gents, I will refer to the wiring diagram again and I've removed the loom tape between the bulkhead and alternator / distributor so will look out for the ballast wire and also test the coil with my meter to confirm the type fitted.

I need to spend some time tracing / cleaning earths and will unplug the flasher unit which I've found under the drivers side dash and test with 12v / earth for operation.

The interior lamp does work via the boot and passenger door switches and also the dash switch. All the door switches have been rewired with more blue cable (!). The drivers door switch has a broken (blue) wire sticking out from the a post and I've traced back to the ends nearby of what I believe to be the original twin purple and white cables from the loom. Will test these for 12 volts then reconnect to the door switch which I understand "earths" the circuit to bring the courtesy lamp on.

Horn wise there are two very ropey looking units which I've removed from the car. One was not connected but two loom feeds dangling nearby (drivers side). The passenger side horn had spurious leads connected and guess what......a blue cable which I've traced back to the horn push (aftermarket steering wheel). I will study the diagram and try trace original wires and the horn relay. Again I suspect someone has hastily bypassed original wiring and relay to jury rig a horn for a past MOT! I will order replacement horn units and try to rewire per original spec. To test the horn push I suppose I could connect a test lamp / meter to the wire , then touch onto positive battery side and see if operating the horn push completes the circuit. I think the horn relay is on the bulkhead next to the hazard flasher.

Reversing lamps wise I have spotted more dreaded blue cable running under the bulkhead and transmission tunnel. I have a replacement plastic tunnel to fit so can hopefully see more once the original is removed and diagnose the issue.

I'm referring to the oil pressure warning lamp that's defective. The HRW lamp illuminates when switched in and the ignition switch operates fine in terms of feeds and cranking / ignition. Car starts and runs readily.

The aux position 1 feed wire had pulled off and had been hacked into for a now disused soldered on cable possibly from an old radio fitment.

I removed the padded surround and back cover from the switch and can see all the cables connected. It seems there is no live feed to the oil lamp bulb holder with the ignition on number 2. I have removed and tested the bulb on 12v which lights up fine. Probe into the bulb holder and to earth produces no voltage reading. So I seem to have an issue between the ignition feed and bulb holder. The ignition warning lamp which I believe originates from the same feed (ignition switch terminal 3) works fine. I'm suspicious of the blue cable described in my post above running from ignition switch terminal 3 to the solenoid  terminal shared with white / yellow feed running to positive coil side! 

I guess that I could piggy back a feed from ignition terminal 3 to the oil lamp bulb holder and if the earth and sender are working this should restore an oil pressure lamp. However I would like to get things back to original. I might have to try unravel some of the loom under the drivers side from the oil lamp bulb holder and see if I can find a break.

Given the presence of spurious wires I would quite like to replace the relevant sections with the proper colour wiring. The loom is otherwise in good condition and doesn't warrant going to the lengths of full replacement. Could anyone recommend a supplier where I could order some ad hoc lengths of different colour cable to match the original loom where necessary? 

As strange as it may sound I'm really enjoying this!

Thanks for the tips and advice.....

Regards.

Dave.

 

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BF,

The ballast wire is white with a pink fleck and most diagrams show it running to the coil. On mine and other mk3s it runs to the solenoid and attaches to the white and yellow. This is electrically the same, as the white and yellow then runs on to the coil. Confusing if you're looking for it on the coil! 

Doug

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3 hours ago, dougbgt6 said:

BF,

The ballast wire is white with a pink fleck and most diagrams show it running to the coil. On mine and other mk3s it runs to the solenoid and attaches to the white and yellow. This is electrically the same, as the white and yellow then runs on to the coil. Confusing if you're looking for it on the coil! 

Doug

My 1972 Mk3 has a ceramic resistor bolted beside the coil, not the pink fleck wire. I'm not sure when the changeover was but I suspect very late for GT6.

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Thanks all. My car was registered in October '73 and is the later non rotoflex version. Will have a look and see what's still there!

Good new is that I am getting TSSC membership as a birthday present imminently from my lovely wife so looking forward to joining the club and putting something back hopefully !

 

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