Fuses

[Oggers]

Can someone please explain this to me. Tail light not working...Checked all connections/earths/wires - all fine. Checked fuse. It had continuity and resistance - 0 ohms. Changed fuse regardless, checked continuity and resistance -  0 ohms. Tail light still not working. Much disconnecting, checking ignition, earths - complete PIA. Thought - check voltage across each fuse terminal - with fuses in place. The 4 on the lower 2 fuses all good - 11.5V, The tail fuse only one terminal 11.5V the other 0V...aha! Changed fuse again - and I now have a tail light. Deeply annoying that the fuse should show no resistance yet does not allow current! Am I going mad?   

[Lobo]

Hmm. Confusing for sure.

My guess is that the fuses have been fine all along, but the live side connection between fuse and it’s fuse holder terminal has been ...”iffy”

So... your meter leads were initially between / touched the fuse HOLDER live terminal and ground. And you saw a difference of 11.5v

Then you put the leads across the fuse (or fuse holder) opposite side and earth... and saw 0v .... because the fuse was not electrically bonded to the live-side of the fuse holder.

Frustration caused you to unseat the fuse a couple of times.... and in doing so ‘cleaned’ the connection enough to finally carry current to the tail lamp.

All I can think of for now...

Simon

PS Not had it myself... but understand the 400F fuse holder can be subject to corrosion / electrical issues. If yours is ‘grubby’ then perhaps consider taking it out and cleaning  the spades various connectors?

[Oggers]

Hmm. Confusing for sure.

My guess is that the fuses have been fine all along, but the live side connection between fuse and it’s fuse holder terminal has been ...”iffy”

So... your meter leads were initially between / touched the fuse HOLDER live terminal and ground. And you saw a difference of 11.5v

Then you put the leads across the fuse (or fuse holder) opposite side and earth... and saw 0v .... because the fuse was not electrically bonded to the live-side of the fuse holder.

Frustration caused you to unseat the fuse a couple of times.... and in doing so ‘cleaned’ the connection enough to finally carry current to the tail lamp.

All I can think of for now...

Simon

PS Not had it myself... but understand the 400F fuse holder can be subject to corrosion / electrical issues. If yours is ‘grubby’ then perhaps consider taking it out and cleaning  the spades various connectors?

Not quite - both fuses showed 0 ohms before placing them between the terminals. When in the terminals, only one end - the live  - showed 11.5V. I too am thinking dirty teminals. Will clean them up. Fuse holder looked fine from the rear......

[robvangulik]

Look at the back side of the fuseholder too...and just saw you already did

[billywingnut]

I had a similar problem with the fuseholder, cleaning it cured the problem for a while but when it failed again a few months later I bought a new assembly from DS

[Oggers]

Cleaned the terminals  and it works -  for now. I hate electrics!