Lost 101 Fuel Gauge and Diff Lock Indication

[fc101]

I know there are no many 101 owners on here but someone might be able to help.

All of a sudden I have lost my fuel gauge and diff lock light. If I provide power direct to the diff lock switch the light works so the issue with this is power is not getting through from the ignition switch.

Likewise the fuel gauge has stopped working - the fuel sender/gauge circuit is on the fuel pump circuit but the fuel pump works fine. All other ignition related functions work fine. Checked the fuses up under the dash and all seem OK.

Just wondering if there might be something added to this circuit somewhere that I am not aware off.

Any suggestions would be appreciated - I haven't pulled the dash out as yet as anyone who has a 101 will know what a pain it is.

Thanks

Garry

[AGAS 5]

Garry,

If I'm reading the diagram correct (?) they both run off the same fuse..... did you try replacing it rather than visual inspection ?

I've found a few old glass fuses that look ok, but have detached inside an end cap.

Cheers,

Pete

[Mick_Marsh]

Yeah, I'm with Pete.
Start at the fuse. Replace with new ones.
Then, check for corrosion at the terminals.

[fc101]

Thanks Pete - unfortunately the fuse box on a 101 is in a very difficult spot up under the dash and hard to get in there.  Likewise in that wiring diagram I put up it would seem that the gauge and sender and the fuel pump are on the same line and I have power to the pump but not the gauge - very confusing.

But you were are correct - bit the bullet and pulled each of the fuses and yep - as you described the filament in one was intact but the end caps were not.  Putting in a new fuse and I now have the difflock light back but not the fuel gauge - very confusing.

So back to the wiring diagram - searching my documents I came across another wiring diagram that is much clearer.  That smudge between the fuel sender and the fuel pump is not a continuous line but earths .  So that clears that aspect.

I can now track the power from the fuse to the gauge behind the dash and then to the sender - might try that tomorrow.  However I did pull the wires off the sender without taking a pic first so may have put them back incorrectly - so will look at that first - I have a spare sender so check it all with that.

Thanks for you input - prompted me to have a look elsewhere.  Much appreciated.

Garry

PS - Mick - thanks for your comment - yes you are also correct 

[Chazza]

Whenever there are "strange" electrical problems on a car, I think immediately of poor earths.

[fc101]

Yes - that is why I normally bypass the earth and create my own - found out the cdl light actually worked and there was another issue either lack of switched power or a bad earth.  Not the same with the fuel gauge but am hopefully will sort that this week.

Cheers

Garry

[fc101]

To wrap this up - first somehow the fuse to a range of items blew - not sure why as it is a 30amp fuse and has been there for at least 14 years.  So the "range of items" were all back except for the fuel gauge. 

I took all the wires off the fuel sender and bridged them with a 24v lead light and the fuel gauge went to half full.  I put the wires on the fuel sender and nothing - back on the lead light and gauge back to half full. Hmmm - I put the wires back on the sender and then went to turn off the ignition and the gauge was reading full as it should as the tank is full.  Everything was working as it should.

Investigated the wires on the sender and could see that there was intermittent contact - through a bit of corrosion on the contacts and the old crimping on the wires was starting to come apart - me pulling and pushing to diagnose things must have pushed them past their use by date - so I will clean and tidy them all up and someday will move the fuse box to a user friendly spot.

Thanks for all the help - was a great help.

Garry 

[Chazza]

Thank you for taking the time to reply Garry, always handy to read of solutions.

Last year my Disco 1 refused to start at Karratha airport. Long story later; the sparky fitted a new positive lead to the pump and then a new earth lead from the battery. It ran beautifully for 20 mins and then played-up. We caught the aeroplane home and the car took a truck. A new fuel pump finally seemed to solve the problem.

So the moral of the story, is to check every connection, at least before a long journey, and to expect that any old car has corroded or loose terminals, even if it is running.

Circuit maintenance should be part of our major service routine,

Cheers Charlie