Triumph Repair: spitfire blowing fuse, amp fuse, rear marker

Question
QUESTION: Jim, I have an 77 spitfire project car. It is blowing the top fuse in the bank of three when the ignition switch is in the on position (first clock ) the engine will start and runs fine. I have a chiltons with the wiring diagram. could there be a problem w/the ignition assembly. any ideas

ANSWER: Scott,

First click is the "auxilliary" position.  Is there a radio fitted?  

And is the fuse large enough for the radio fitted?

If the car is starting and running fine with the fuse blown then it's not the igntion assembly.

Cheers,

Jim

---------- FOLLOW-UP ----------

QUESTION: this car has basically been a total tear down and rebuild. the body was remover from the frame so both could be painted.I have built a walnut dash so all the gauges have been pulled and reinstalled. there is currently no radio wired. there is a 15 amp fuse in the slot that is blowing.

Answer
Scott,

Then I hope the blue factory wire for radio power feed is properly insulated?  

According to the drivers handbook, the late Spitfires have 3 fuses.

White cable feed from ignition switch 35Amp fuse.  

Windscreen wiper
Fuel indication
temperature indication
stop lamp
reverse lamp
turn signal
seat belt warning

red/green cable feed from light master switch  10 amp fuse
front parking lamp
front marker lamp
rear marker lamp
tail lamp
plate illumination lamp
instrument illumination

brown cable feed direct from battery 35 amp fuse
headlamp flasher
key warning
courtesy light
horn
hazard warning

So it sounds like the top fuse is fed from the ignition switch.  By the factory book it should be 35 amp, not 15 amp.

Once the proper size fuse is fitted, if there are further problems then it's time to trace all the wiring to see if a wire is cut or grounded innappropriately.

Cheers,

Jim