[Shaungti]

Hey guys
After some help with my Sierra with a gti conversion.
The wiring is a little bit of a mess. Car runs fine. But I have no dash functions, so no tacho fuel temp oil pressure light or brake warning lamp.
There is a fuse missing from the fuse block. 15a rated and blows when ignition is on but unsure because of the conversion what is run off the wire now. B/W runs too alternator and dash cluster and a few other places

[fordem]

I hate to say it, there's not much we can do either - the fuse might be the one that powers the instrument panel cluster - but, we don't know for the same reason you don't know.

Wire a small 12V bulb in place of that fuse (so you're not repeatedly blowing fuses whilst testing - if the bulb lights at full brightness, the short that is blowing the fuse is still present) and start disconnecting the things powered from that fuse one by one - alternator first.

[Gwagensteve]

Is the alternator charging?

If there is no power to the exciter, the alternator shouldn't be charging if this circuit is dead.

The computer and fuel pump should be on their own fuses and have their own relays, one for the computer and one for the fuel pump. ( I hate dealing with other people's wiring)

On a Sierra Black with white runs the dash, excites the alternator, and opens the fuel cut solenoid to make the car run. it could be used to provide a signal to the EFI relay to power up the computer, and so poor wiring between the stock loom and the EFI relay could be source of your fault, or, as Fordem suggests, there could be a fault with the alternator.

1.3 Sierra wiring looms are generally very reliable - It's people's modifications that are normally the problem.