GTD Wiring schema - fault?

[PeterR]

After some years running with no problems something happened this summer. I had finally got the a/c working very well (after fitting new condensers). Returning home, engine refused to stop on the ignition switch. But what was incredibly worrying was the fact that the ignition switch had become too hot to touch!! So that was quickly replaced. Taking a close look at the wiring diag suggests that the live feed to the igntion switch comes direct from the battery (actually via the starter solenoid), without any protective fuse or relay. This is potentially incredibly dangerous - anyone else discovered this situation?
I suspect the a/c contributed to this situation. Some terminals on the INDAK switch were impressively 'cooked'. But the a/c does not figure on the wiring diagram (the hand-drawn item that we probably all have by now). I obtained that wiring diag from a CD passed on by Bud Jones, who actually added a terse comment to his copy which reads 'See notes on previous page about installing <can't decipher text> fuse block to power relays. This lowers ignition switch operating temp.' So it seems Bud encountered this problem (or should this be 'design oversight'?!), but I cannot work out his solution.
I would be most interested to hear if others have encountered this problem, and how they addressed it. Meanwhile, I'm flat on my back under the dash mapping out that jungle of spaghetti!
Peter

 

[PeterR]

[For some reason my text was truncated - was it too long? Here the remainder...}

...actually added a terse comment to his copy which reads 'See notes on previous page about installing <can't decipher text> fuse block to power relays. This lowers ignition switch operating temp.' So it seems Bud encountered this problem (or should this be 'design oversight'?!), but I cannot work out his solution.
I would be most interested to hear if others have encountered this problem, and how they addressed it. Meanwhile, I'm flat on my back under the dash mapping out that jungle of spaghetti!
Peter

 

[PeterR]

... cannot add text, all truncated.

 

[Howard Jones]

Yes. The original GTD wiring scheme is not a good one because of that. I changed mine but its been about 20 years so I would have to find the drawing, But it went something like this. Main B+ to 4 fuse accessory fuse block. Then I attached the solenoid lead to the fuse block buss and disconnected it from the ign switch. Used 1 of the fuses to feed the ign switch and 2 of the the others for fog lights, and gearbox oil pump and 4th for other power circuits that went through the key switch. Or something like that.

 

[JP Verweij]

Taking a close look at the wiring diag suggests that the live feed to the igntion switch comes direct from the battery (actually via the starter solenoid), without any protective fuse or relay. This is potentially incredibly dangerous - anyone else discovered this situation?
....
Peter

Nothing to worry about as many cars from the '70s & '80s have this.
All Ford Capri's, Cortina's, Taunus, Granada's, Escort's & Fiesta's mk1 & 2 have a live feed, unfused to the ignition switch (red wire) and another one unfused to the gauges (yellow).
Non of these are fused or fusible link wires.

My KVA runs the complete loom of a Fiesta mk1. Unfused as OEM.
Both my Fiesta's mk1 & 2 still run without issues after 40 years.
I think your AC is wired wrong asking to much from the ignition switch so it fried. Should be powered by a relay instead of directly from the ignition switch.
Heater systems in Capri's & other old skool Fords are also switched by a relay.

 

[PeterR]

Thanks for both of these comments - helpful, and reassuring. Gives me a good steer. My, but it's a tight squeeze working on the wiring under the dash!

 

[Neil]

"My, but it's a tight squeeze working on the wiring under the dash!"

That's why I made my switch/circuit breaker panel removable. The "XXX" breakers are for future use.

 

[Bob Putnam]

I didn't trust the Lucas ignition switch, so I only use it to trigger a main relay.

 

[PeterR]

Bob, your wiring diagram - most impressive, thanks so much for pasing it on. It is the first time I have seen a diagram incoporating the a/c. Nice to see how the Indak switch connects. I absolutely take your point about the Lucas switch. I recalll the comment by Bud Jones that he took steps to stop the ignition switch overheating. I wonder why this was happening with his car? I can see that diagram of yours is going to give me many happy hours of contemplation!

"My, but it's a tight squeeze working on the wiring under the dash!"

That's why I made my switch/circuit breaker panel removable. The "XXX" breakers are for future use.

View attachment 133583

Yes, I can see how the existing system drove you to such a radical solution. That must represent a considerable amount of time. Well done!

 

[PeterR]

(Sorry, replies got mixed up - last directed to you, Neil).

 

[Neil]

(Sorry, replies got mixed up - last directed to you, Neil).

Thank you, Peter. This is what the rear of that panel looks like.

 

[Howard Jones]

My SLC pannel. It's not as bad as it looks.

 

[PeterR]

Neil, Howard, your respective solutions speaks eloquently of the short comings of the existing wiring! I think I would need a much more reliable wiring diagram before undertaking such a project.
Meanwhile, another profitable session on my back under the dash this afternoon. One quick question (and it may be GTD specific). I can force the a/c to come on by closing a circuit, at which point I hear the a/c relay switching in. But I absolutely cannot find it! It seems to be somewhere in the vicinity of the evaporator - it can't be inside it, can it? Can anyone advise?
Oh, last question - Bob, would you have a key for your wiring diag that you could share? That diagram aided me significantly this afternoon, much obliged.
Thanks all,

 

[Neil]

Neil, Howard, your respective solutions speaks eloquently of the short comings of the existing wiring! I think I would need a much more reliable wiring diagram before undertaking such a project.
Meanwhile, another profitable session on my back under the dash this afternoon. One quick question (and it may be GTD specific). I can force the a/c to come on by closing a circuit, at which point I hear the a/c relay switching in. But I absolutely cannot find it! It seems to be somewhere in the vicinity of the evaporator - it can't be inside it, can it? Can anyone advise?
Oh, last question - Bob, would you have a key for your wiring diag that you could share? That diagram aided me significantly this afternoon, much obliged.
Thanks all,

Peter,

My car is a home built of my own design so I had complete freedom in its construction. My philosophy is "Keep it simple".

 

[PeterR]

Peter,

My car is a home built of my own design so I had complete freedom in its construction. My philosophy is "Keep it simple".

Then all I can say is amazing - well done!