tr7triumph.com

anybody know where I can find the fuse for the taillight/side marker
lights for my 77 FH USA TR7? Something in that circuit is causing a voltage drop that prevents my headlights from popping up. If I take the plug out of the main lighting switch, and put a jumper wire
from the brown to the blue wire(the headlight actuater circuit), the
headlights pop up, and STAY up. With the running lights on, I only have about 2-3 volts to the headlight relays, not enough to power the motors. The 4 fuses behind the glove box are apparently not the ones for the running lights. I want to find an easier way to isolate that circuit without unplugging the main lighting switch. Thanks

I suggest it may be bad earth connections - and when the side lights are ON - there is no earth path for the others which can otherwise leak to earth through the sidelight bulbs.

I don't think there is a fuse specifically for the side lights. The lights are wired through the master switch panel which gets its power from the head lamp motor circuit breaker.


nick
'79 TR7

They are in the fuse box at the back of the glove box. There are separate fuses for the side lights each side. On my (UK) '81 they are 7-8 and 9-10, 15 amp (top row 2nd and 3rd from the left). I think the fuse boxes varied with the year and market (US ones may be like UK turned upside down when they moved to the other side?) Note that the fuses are not the standard glass fuses you get in parts stores today, they are a little shorter and rated for continuous feed and blow current.

Alan
Saab 9000 Stg 1
Saab 9000 2.3 FPT Auto
'81 TR7 DHC

my wiring diagram in the Haynes Manual (which could be wrong) shows five fuses. one fuse , that I believe they list as 25 amp, is specifically in line (series) with all the side and tail lamps.
If there really is no such fuse, I could believe it to be possible for leaking voltage to light the lamps. Am I correct that the headlamp circuit breaker is a separate component near the fuse box?
I think it's a sealed device that automatically resets. I am not at home right now so I can't look at the manual or the wires to be 100% sure. Maybe that breaker is what the manual considers a fuse, but would Triumph really put all the lights through one common fuse?
The manual of course does not show the numbers of the locations for any of the fuses, but I was looking for something connected to green or red wires which feed these lamps.