Using inline fuses?

[Blonde Healey Girl]

It seems a while back a few of Y'all mentioned using inline fuses to protect a few things on your LBC. Saying that the factory installed 35 and 50 amp fuses were too broad to protect properly. I remember someone said that you should fuse the license plate light because if you should get hit from the rear that it could short out the wires and catch on fire near the gas tank. Since our new paint job, I have been reinstalling and rewiring the rear tail lights and noticed that the wire from the port side tail light going over to the plate light was all melted and bare in places. Should I put a inline fuse on just that leg and if so where would the be the best place.Or,how far up stream? Try to protect all tail lights? And one last question!!! What size fuse? thanks!

 

[Dave Russell]

The 50A fuse only supplies the horn. The 35 amp supplies some of the circuits, many more are not fused at all.

I would put a 15 amp in line fuse between the light switch post & the two red wires coming off that post. Usually wires #41. This will protect the front & rear running light circuit (side lamps) & the plate lamp, & the dash lamps.

Some folks also fuse the OD solenoid & also the fuel pump in the same way. These circuits can be accessed at the OD relay terminal C2 & the fuse block terminal A3 for the fuel pump.

The Brit 35 & 50 amp fuse ratings correspond roughly to USA ratings of 20 & 35 amps.
D

 

[Keoke]

The wire you mentioned as being charred is very easily replaced.For that circuit I also include a small 1A fuse just inside the boot.---Fwiw---Keoke

 

[JamesWilson]

[ QUOTE ]
I remember someone said that you should fuse the license plate light because if you should get hit from the rear that it could short out the wires ....

[/ QUOTE ]

The position of the fuse should allow it to protect your car from the elctrical hazard of an accident, so the fuse should be placed "upstream" of the section likely to be damaged.

I suspect this particular circuit was singled out for fusing because the wire passes through the shroud and is more susceptible to both accident damage and wear and tear. The other wiring for the rear lights is not so exposed to damage and does not seem to need any special protection.

Pick someplace easily accessible too- perhaps near where that wire leaves the rear wiring harness, or just inside from where the wire passes through the shroud.

The fuse should be 1 amp. The lamp is rated at 6 watts- divide by 12 volts to give the amperage load ~.5, add a margin for minor variations and 1 A. will do. AMPS = Watts / Volts.

It would also be highly advisable to use a little rubber grommet on the shroud where the wire exits to the lamp- otherwise the metal will rub against the wire's insulation and may over time cause a short and that melted wiring you saw.

Good luck with it....

 

[SHG]

As long as we're on wiring, would anyone have any idea why my front blinkers are working but nothing happening with the rear blinkers? I'm not clear where to find the relay or connections for the rear blinkers to check if something is off, dirty, chafed, etc. Thanks.

 

[Dave Russell]

[ QUOTE ]

The position of the fuse should allow it to protect your car from the elctrical hazard of an accident, so the fuse should be placed "upstream" of the section likely to be damaged.

I suspect this particular circuit was singled out for fusing because the wire passes through the shroud and is more susceptible to both accident damage and wear and tear. The other wiring for the rear lights is not so exposed to damage and does not seem to need any special protection.


[/ QUOTE ]
I believe the late BJ8's had a separate fuse factory installed in the boot.

I certainly agree with the "upstream" part. However I would prefer "more upstream". The entire wiring harness running from front to back is clipped to a vulnerable section of the frame, being nearly on the inside corner. And secured with non insulated metal clips. Thus my preference for fusing at the back of the lighting switch to protect the entire rear wiring section & the front outboard lighting which is also vulnerable.
D

 

[Dave Russell]

[ QUOTE ]
As long as we're on wiring, would anyone have any idea why my front blinkers are working but nothing happening with the rear blinkers? I'm not clear where to find the relay or connections for the rear blinkers to check if something is off, dirty, chafed, etc. Thanks.

[/ QUOTE ]
If you have an earlier car, there is a flasher control relay mounted on the LH inner fender panel. Later BJ8's (separate turn signal lamps) did not have this relay & used a more conventional control circuit. There is a wiring diagram in the "Knowledge Base" that you can "maybe" get to down load, I couldn't. Don't know if it is for the early or late cars. If you have the relay equipped car, the relay can be opened & the contacts cleaned.
D

 

[GregW]

Hi Scott,
Double check those connectors that you disconnected when removing the trafficator. Sometimes the metal inside gets corroded and also doesn’t pinch very well on the bullet.

 

[GregW]

Hi Dave,
The wiring diagram in the Knowledge Base is for the late model BJ8’s. I can email you the PDF directly if you want.

 

[JamesWilson]

[ QUOTE ]
I believe the late BJ8's had a separate fuse factory installed in the boot.

[/ QUOTE ]

They did. Mine had that wiring stripped out so I'm not sure where exactly it was placed.

[ QUOTE ]
I certainly agree with the "upstream" part. However I would prefer "more upstream". The entire wiring harness running from front to back is clipped to a vulnerable section of the frame, being nearly on the inside corner. And secured with non insulated metal clips. Thus my preference for fusing at the back of the lighting switch to protect the entire rear wiring section & the front outboard lighting which is also vulnerable.
D

[/ QUOTE ]

True. This would entail fusing either each circuit, or the whole feed through the lighting switch.

When I got it the wiring under the car was dangerous with whole sections of insulation stripped off. I intend on running the replacement harness down the trans tunnel on top of the chassis, and to fuse each major curcuit independently.

 

[SHG]

Hey Greg. I was able to download the wiring diagram. I have a 64 BJ8, so it's a little different, but not enough to make a big difference. I just checked all the bullet connectors, the relay, the fuses and box, and found nothing wrong. The wierd thing is that my rear blinkers don't work, which doesn't make sense according to the wiring diagram as it should either be left or right, but not front or back. The rear lights work with the headlights on, but don't show the brake light. Also, the horn doesn't work, and I just put a new 50A fuse in. I had just finished rebuilding the trafficator (which still doesn't cancel!!!), and I know the horn connections are good.

There are just way too many issues going on, and I keep checking and everything keeps looking fine. But obviously, I'm missing something.

 

[JamesWilson]

[ QUOTE ]
As long as we're on wiring, would anyone have any idea why my front blinkers are working but nothing happening with the rear blinkers?

[/ QUOTE ]

Your profile says you have a BJ8. Is this the car with which you're having the problem?

Earlier cars had a flasher relay. They used bulbs with two filaments at the rear. The less bright was used for the running lights on one circuit, the other brighter filament served the dual purpose of signal and brake light. The "Bentley" manual provides a discussion (page N15) of troubleshooting a faulty relay. If its an early car that would be one place to look.

Other things to consider and if it is a BJ8 that you're having difficulties with then check:

1) do the rear turn signals share a common ground that is bad?
2) since the front signals work I wouldn't think that there was a problem internal to the trafficator, instead there may be difficulties with the connectors once the wiring exits. If you worked on it did you re-connect the wires to the rear signal lights as well as those for the front?
3) Its also possible that the wiring to both left and right rear signals was damaged but the odds are against both being damaged/going bad at the same time.

I hope this helps... electrical problems are sometimes tricky even when you're right there....

 

[SHG]

1) do the rear turn signals share a common ground that is bad?

they have a common ground, but I checked it and it looks fine.

2) since the front signals work I wouldn't think that there was a problem internal to the trafficator, instead there may be difficulties with the connectors once the wiring exits. If you worked on it did you re-connect the wires to the rear signal lights as well as those for the front?

All the bullet connectors are in place, though they are in a horrible spot to really be able to see what's going on with them. However, that said, I did check each connection and they are all tight.

3) Its also possible that the wiring to both left and right rear signals was damaged but the odds are against both being damaged/going bad at the same time.

the wiring goes from the left rear to the right rear. But remember, the brake lights aren't working either. While this would make the ground a more likely candidate, as I said the ground looks fine.

The whole thing just isn't making a lot of sense to me. It would seem that some connection to the rear lights is bad, but they work with the headlights. Just wierd.

 

[JamesWilson]

[ QUOTE ]
...the wiring goes from the left rear to the right rear. But remember, the brake lights aren't working either.

[/ QUOTE ]

I'll assume these problems are all related. (though its possible they aren't)

I presume you've checked and found that there is no power coming from the front of the car to either the brake or signal lights.

My wiring diagram shows a set of connectors for the trafficator and a second set drawn so that it appears they're located together. That second set also feeds the dash indicators. Did you check those connectors and lights too? I'll presume so.

That then leaves:

Can you check under the car for damage there to the wiring. A good bash could crush one of the retaining clips and cut the insulation (and maybe even the wiring) to interrupt or short-circuit the signals and brakes. You're having problems with three different circuits here- the brakes and the two signals. The running lights and fuel pump wiring also runs alongside those, I think- are you having any problems with them? But they may have been protected by the other wiring and not damaged.

 

[Keoke]

SHG, lets see if we can at least make the horns work. 1st make certain you have 12v present on both sides of the 50A fuse. Now go to the horns and see if there is also 12V at one of the horn terminals and tag it "HOT".Now diconnect the wire on the opposite terminal and momentarily ground that terminal if the horn works you have either an open ground circuit from the trafficator or somewhere in the wiring harness to the horns.-Let us know how you get on---Keoke

 

[SHG]

Hi James,

No damage under the car (checked that too), but I'm not aware of a second set of connectors. Does you diagram show where they are? Thanks

 

[SHG]

Hi Keoke, I'm going to have to wait until light to go back to work on this. I was talking to a mechanic who thinks that this is all related to my trafficator rebuild, and that I may have mixed up the wires. I swear I made a diagram, but he says he sees it all the time. It may be time to turn this over to a smarter, taller, handsomer fellow than me.

 

[shorn]

Have you checked with a multimeter to see if the bulbs (should be 1157's)work. Perhaps one filament is burnt out on both rear bulbs. That would account for both the brake lights and turn signals being out.

 

[Keoke]

Yep! SHG, I think there is sumpin wrong in that Flusterator too.---Keoke--- /ubbthreads/images/graemlins/laugh.gif

 

[healeygal]

Referring back to the original question, a fellow Healey owner has installed a larger fuse block on his Hundred to replace the original 2-circuit fuse block - it uses the same mounts as the original, works for BN1 thru BJ7's, and as you can see from the picture, accommodates 7 fuses.

Sharon
BN1