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Tips
Tips

BJ8 Tachometer and Fuel gauge stopped working.

Ok this sounds interesting......because I recently had someone replace a rocker for me and the day I picked up the car I noticed that the steering wheel had been pulled right back i.e. at its furthest extension, and tightened too. I got it back to where I normally have it but perhaps this could be the issue - indicator wire in the column.

I'll still troubleshoot it the normal way but will keep this in mind.

Was that hard to fix, Steve?

Bobby

No, Bobby, it wasn't hard to fix. I had to pull the turn signal unit out of the steering wheel far enough to work on it. Had to remove the three screws attaching the two halves of the unit to expose the wires attached to the terminals. I found some exposed wire on the power input wire to the turn signal switch. There isn't much room to effect repairs to wiring inside the trafficator except for replacing terminals, so I decided to replace the whole steering column harness just to make sure I wouldn't have to do a repair again anytime soon.
 
UPDATE:

Disconnected the indicator circuit at the flasher relay and have driven the car now for several kilometres, replicating all of the previous conditions when it would blow, and lo and behold, the fuse is still fine.

So, I have an intermittent short in the indicator circuit somewhere. The problem with it being intermittent is that it's hard to replicate but I'm confident that the short is there somewhere.

Everything is fine at the lights themselves, all connections are in good order, so next on the list to check is probably the steering column and steering wheel/ trafficator. Not relishing the idea of taking this apart but we'll have a go. Any tips welcome.
 
UPDATE:

Disconnected the indicator circuit at the flasher relay and have driven the car now for several kilometres, replicating all of the previous conditions when it would blow, and lo and behold, the fuse is still fine.

So, I have an intermittent short in the indicator circuit somewhere. The problem with it being intermittent is that it's hard to replicate but I'm confident that the short is there somewhere.

Everything is fine at the lights themselves, all connections are in good order, so next on the list to check is probably the steering column and steering wheel/ trafficator. Not relishing the idea of taking this apart but we'll have a go. Any tips welcome.
A few of them I've seen shorted, including mine, it was right where the wire harness comes out of the steering box and was rubbing the stator tube. If it's an adjustable wheel, push the steering wheel as close to the dash as possible then inspect the wires coming out of it(I'm going from memory on this but I believe it's what I did). Any bare wires can be protected by shrink tubing.
 
UPDATE:
Righto. I just drove the car for 30 minutes without a problem. Ironically, to go and buy spare 35A fuses for my day of diagnostics! I only had 3 wires connected to the fuse blockl; the tacho/ fuel, indicators and brake lights.
Plenty of indicating and braking; still no blown fuse.

The fuse blew twice on the way back....and on neither occasion was I indicating...but on both occasions the conditions were as follows:

Straight line
Hard acceleration
No indicators on
No large steering inputs.

On one occasion the road was flat and good surface, on the other occasion...and actually I've done it twice at the same spot, the road was very steep; the car initially on a flat surface, then a left hand bend (not sever) and then hard acceleration in third to get her up the steep hill and within a second of putting my foot down, a juddering throttle response, fuse blows and back to normal throttle response.

So, the problem seems to be related to movement; specifically acceleration. I have blow the fuse before when accelerating to cross a street; so it's not speed related, but the revs being up there seem to be consistent. I've driven over bumps before with no problem so I'm not convinced it's the angle of the hill; my driveway is steeper and I've made it up there before.

Whether it's the tacho not enjoying high revs or the fuel gauge perhaps, I'm not sure. Next step is to check the cables behind the instruments and hope I find something I didn't see when I first checked.

Could it be the tacho dial itself perhaps?

Bobby
 
UPDATE:
Just managed to get it to blow with only the fuel gauge and tacho attached to the fuse block....no brake lights, wipers, heater or indicators attached at all.

Going up a steep hill, hard acceleration, low speed; this time it was up my driveway.

Checked cables behind the gauges and all seems fine. Struggling to work out why the acceleration is affecting it...I've had the revs up to 3000prm wihtout blowing it, and going up the driveway it wouldn't have been that much.
 
Hopefully the last update......!

Having inspected the coil to tacho connection, I traced the wiring back and then checked the loom where it comes out of the firewall - lo and behold, it's been touching the rearmost of the cylinder head bolts which has rubbed through the harness and through two green wires. The exposed wires aren't touching each other but if the engine moves backwards on its mounts e.g. under hard acceleration, the bolt would touch the exposed wiring.

I've temporarily taped it up with electrical tape so I can go and test it, now with everything connected back up to the fuse block.

If that works I'll be a happy boy!

EDIT: It works....and it's a beautiful sunny Autumn Saturday on the Central Coast of New South Wales, it's 26 degrees (Centigrade, not Farenheit!) and I think the poor old girl deserves a bit of a coastal cruise.

Thank you to everyone for helping - such good tips and advice, you're all amazing. Particular thanks to Ray Carbone for sending personal emails with detailed instructions and descriptions.....you are the man, Ray. You are the man.

Bobby
 
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