View Full Version : Spitfire Blowing fuses in my 79 spit

06-01-2011, 12:17 PM
Hello all, hope everyone is well on this first day of June.
Problem starts with my sister in-law allowing her two beautiful girls (they really are lovely) sit in my spit and monkey around. No worries, Iím not an ogre, and besides they are just so cute sitting in it.

Anyhow ever since then I keep blowing the fuse that's in charge of the horn and high beams, coming off the turn signal indicator.

Replace the fuse, hit the high beams a couple of times and pop.

Any suggestions?


06-01-2011, 01:39 PM
Do the high beams work OK if you turn them on through the regular headlight switch, instead of the "flash to pass" feature? If so, I would suspect a problem with the switch itself. It's kind of fragile, and very tempting to young hands.

When I was about 3, I managed to release the handbrake and wreck the family car, or so I'm told. All I can remember is the moment when the open car door hit the wall ...

06-05-2011, 06:30 AM
Thanks Randall, I did sort of the same thing with my grandma's corvair ( really miss that car).
It seemed to go while doing both. Interestingly i discovered a little box of Lucas fuses and installed one of them, has not blown since.

You don't suppose it was some sort of quick vs slow blow issue?

I'm not looking forward to tearing apart the switch and all.

06-05-2011, 06:35 AM
Did one of them by chance push in the cigar lighter? It's on the same fuse and if you had too small a fuse in when you turned on the high beams you may blow it.

06-05-2011, 08:46 AM
Also check the chrome "fold down" map light. Always tempting to play with and sometimes wont shut off.

06-05-2011, 09:12 AM
You don't suppose it was some sort of quick vs slow blow issue?
Could be. I've never seen a "slow blow" Lucas fuse, but that doesn't mean they don't exist.

What size fuse are you using? And are you running stock sealed beam headlights?

06-07-2011, 11:19 AM
You may have hit it on the head. Was using aftermarket 12A, when what was in there was a Luca #35 15A. After finding that little box of Lucas fuses it hasn't done it since. ( this could just be a case of user error).

Though I am interested in the issue with the lighter as mentioned by Rhody. I may just pull the plug on that anyhow as I haven't had a need for one of those in about 5 years.

RE: the map light, I don't have one, must not have been an option in 79, though I wish it was.

06-07-2011, 12:42 PM
I don't have my manual handy, but a Lucas 15 amp (or aftermarket 12) both seem awfully small. As noted, there are a lot of things on that circuit, and just the headlights will be drawing roughly 10 amps.

06-09-2011, 09:18 PM
Ok well I feel like a dolt, upon further inspection it appears that they are Lucas 35 amp fuses.
Perhaps this was my problem all along.

06-09-2011, 11:52 PM
That would explain it. Don't forget that the Lucas rating system is different, making those roughly 17.5 amp fuses. Some Lucas "35 amp" fuses even have a piece of paper inside that says 17.5, but not all of them do.

06-12-2011, 04:40 PM
Well I am happy to report that so far so good. It appears this was my problem all along.
Picked up some more fuses, from my main man Scott at Team Triumph, and they are just as you describe Randall, little slip of paper, Lucas #35. Prince of Darkness fortune cookies?

Ok poor joke. Anyway thanks for the advise my man!