Fuse issue?

[TrevS]

Hi all

The e-type was out for it's final outing of the year at the weekend to Silverstone for a Pistonheads event which was a lot of fun but on the way home a friend noticed that we didn't have any brake lights. So after getting the car home and taking a look we also noticed the horn isn't working and neither in the reverse light. Looking at the fuse box diagram it seems the horn is also on the same fuse as the brake lights so I think it might be a fuse that needs replacing.

How often to fuses go in these cars, is it a common issue? Also could someone tell me what size the fuses are as I don't have access to the car this week to measure them and want to get some fuses ordered.

As always your help is much appreciated

Trev

[ralphr1780]

Trev, I guess that you still have the original style fuse holders.
It is quite frequent that some light oxidation settles in there on the fuse contacts and the fuse ends. I found that it is even more important on the fuses that gets less "solicited" such as the one you mention.
In your case, I would start by cleaning / de-oxidising the contacts and fuses.
I do this as a routine job every spring.

[Gfhug]

Trev, can't remember if they are 35 or 50 amp fuses, but search for GFS35 fuses (17 amp continuous, 35 amp blow) as modern 35 amp fuses are different to the older style. Or similarly for 50 amp fuses.
Sadly, not many of these older fuses around.

Geoff

[ETTony]

If you are lucky the fuse will just have been dislodged and moved to one side, enough to brake contact.

[TurboScab]

I think that's fuse 6. I'm pretty sure it's a 35amp. It also covers the radiator fan motors so it's the one you don't want to blow on a hot summer's day in heavy, slow-moving traffic.

I speak from bitter experience

[chrisfell]

Before you go changing a fuse, it would be prudent to establish a cause. The No6 fuse is a chunky one that wouldn’t blow unless there was a short circuit, live to earth somewhere. I had the very same issue recently, the cause was one of the dash light bulbs, which had come loose from the speedo and was shorting on the speedo housing.

[TrevS]

Hmm, weird. I managed to get to the garage tonight to take a look and replaced the fuse. The removed fuse looked in good condition and I found a few spares that I remembered I had as the previous owner left a couple of packets in the car when I bought it.

Anyway changing the fuse hasn't fixed the issue. The horn is working although I suspect it was before but I hadn't had the ignition on and it doesn't appear to work when the car is switched off. So I still don't have working brake lights or reverse lamp.

Is the next thing to do to check the bulbs in the lights as would a blown bulb cause issues with both lights? Otherwise I guess its a wiring issue

Trev

[cactusman]

As has been said the fuse holders are known for oxidizing and then intermittent connection. Also...cheapo fuses tend to have the fuse element inserted into the glass tube and folded over at each end with the end caps then slid over...the cap is just an interference fit to the fuse element and I have had corrosion between the fuse wire and cap cause issues. Old style or good quality fuses always have the fuse wire soldered or welded to the end caps.
If you only have an issue with the brake lights and have eliminated fuse issues and failed bulbs then I would look at the hydraulic actuator switch fitted in the front brake circuit on the picture frame (S1 cars). OE ones last ages but the reproduction parts (e.g. intermotor branded) are rubbish and rarely last more than a year or so. Try switching on the ignition, removing the turntables to the switch and connecting together. If the brake lights illuminate then the bulbs, wiring and fuse are fine. You have a dud switch. SNGB have a new custom one on trial......I have one...not sure if it is on sale yet but thus far mine has been fine.

[Gfhug]

If it is the hydraulic actuator then read through this upgrade topic. Well worth doing whether it is that actuator or not.
viewtopic.php?f=9&t=3134

Geoff