Fuel Warning Light

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iandvl
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Fuel Warning Light

Post by iandvl » 05 Mar 2018 09:56

I left for Piesangkloof yesterday to drive the route with a group of people I know. Those who have been to Piesangkloof will know that there is about a 1 km stretch of dirt road before entering the gate (normal dirt road - nothing weird). In any case, drove up the dirt road, parked the truck, and chatted with the people prior to doing the drive.

Starting up right before the drive, the "fuel warning light" was flashing. It has never done that before, ever, apart from one occasion when it came on briefly and I ended up stranded next to the road without fuel... :rolling: :rolling: And since Sunday, it's been doing this intermittently since then.

I think I've worked out more-or-less what is going on. The fuel gauges work fine. The amount of fuel I have on-board matches in terms of the kilos I've done. I also activated the subtank yesterday to test the gauges. The main gauge rose, sub gauge dropped. In short: the gauges are working perfectly...

I dug through the manual this morning.

I see that the fuel gauge sender will give different resistances between terminals 1 and 2 according to how much fuel there is. ie: This will show how full the tank is on the fuel tank gauge. This is not an issue, as the gauges are working.

But, the fuel gauge sender will provide no connectivity between pins 2 and 3 on the sender when there is fuel. And when fuel is low / empty, there will be connectivity. So, this would explain the issue.

In short: I'm looking at two possible problems.

1: My fuel gauge sender is faulty.
2: I have an intermittent short on the harness between pins 2 and 3.

I know that the fuel sender unit is underneath the boot. But before I start stripping trim, panels and similar, I was just curious as to whether anybody knows how the harness for this thing is routed ? ie: Is it routed along the chassis ? Is it routed through the cab ? It would save me a heck of a lot of frustration trying to find it all.

Thanks in advance.

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Re: Fuel Warning Light

Post by biggles » 05 Mar 2018 11:34

Just from spending some time under the troll routing cables for the dual battery and what not. The cables are probably routed along the chassis.
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Re: Fuel Warning Light

Post by Jorrie » 05 Mar 2018 13:22

If you take off the lower door sill covers of the left hand door openings you will find a loom there. I do not know if that might be what you are looking for.
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Re: Fuel Warning Light

Post by iandvl » 05 Mar 2018 13:31

Thanks for the responses. I also got a call from Tinus earlier. And that is to disconnect the fuel sensor at the plug for a while, drive around a bit and see if the issue is gone. That would indicate whether it's an issue with the float thingy / sender, or an issue with wiring. I'll see if that works first. Will post resolution when I figure it out.

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Re: Fuel Warning Light

Post by iandvl » 05 Mar 2018 18:08

I did a quick inspection of the harness today before the rain ended my problem solving....

In short, I recently had a back bumper installed by a (supposedly reputable) fitment centre.

I have not yet opened up the split sleeving to see what the harness looks like - the rain we had ended that. Will see what it looks like tomorrow.

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Re: Fuel Warning Light

Post by Rhett » 08 Mar 2018 09:32

Did you check again to see if you could source the problem?
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Re: Fuel Warning Light

Post by iandvl » 08 Mar 2018 10:15

Rhett wrote:
08 Mar 2018 09:32
Did you check again to see if you could source the problem?
I've been very busy this week, and have had several serious family issues to sort out. In short, no. I'm hoping to figure this out this afternoon, but that will depend on the weather. Don't really feel like rolling around under the vehicle in the mud... :rolling: :rolling:

Will post when I've figured it out.

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Re: Fuel Warning Light

Post by Rhett » 08 Mar 2018 12:07

:lol: I fully understand, this weather is nice for lying on the couch, not lying under your car.
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Re: Fuel Warning Light

Post by iandvl » 12 Mar 2018 09:36

Just an update on this matter....

To answer clarify things :

1: Cables are routed from the fuel sender unit on top of the tank (get access to it via the access panel under the carpet in the boot, along a chassis member to the left-hand side of the vehicle. There it joins the other main harness, running along the main chassis bit to the front of the vehicle.

2: In my case, the issue was cowboy electrical repairs by the previous owner. Once I'd opened the access panel, I noted a large chunk of insulation tape peeking out from underneath the split sleeving. Opening the sleeving and removing the tape showed that there was a short between two wires. I assume that when the harness was moved a little bit during the bumper fitment, this put a bit of strain on the previous repair. After driving the short dirt road to Piesangkloof, the shaking must have been the final straw.
tank1.jpg
tank1.jpg (159.62 KiB) Viewed 1367 times
Whilst I was busy, I decided to remove another offensive piece of wiring I've known about for a while and been worried about - seriously, as it is a major fire risk. But I've not got around to turfing it yet.

The previous owner had a relatively thick cable running from an ignition live circuit to the back (presumably to power a trailer / something). I'd determined it to be there quite a while ago - properly insulated it and taped it to the chassis with the idea to trace the cable at some point. Upon opening the hatch for the fuel sender, I gathered that the cable was routed through the hatch, underneath the carpet, along the door frames and into the engine bay. I later traced the relay, and managed to get rid of everything. Very happy with that, as I've been super worried about it for months...
tank2.jpg
tank2.jpg (163.08 KiB) Viewed 1367 times
tank3.jpg
tank3.jpg (210.67 KiB) Viewed 1367 times
That is all gone now. On a side note, whilst tracing the wiring, I also noticed that the vacuum pipe for the diff-lock runs underneath the door beading on the driver's side (highlighted in red in this photo). Just thought I'd post it here in case someone was interested in the routing of that pipe one day...
tank4.jpg
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Re: Fuel Warning Light

Post by ricster » 12 Mar 2018 10:39

Well spotted on the difflock hose/pipe !!! :thumbup: :thumbup:
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