Fuel Guage Not Working

[Gohn 68]

evenin !

electrics, bloody electrics

my fuel guage is dead brown bread

I have plenty of fuel in the tank, and the needle is showing empty

I have already changed the Fuel Tank Level Sender Unit

when I turn on the ignition to the first mark, there is no movement at all from the dash fuel guage needle

have read thru many past posts to try and get a lead on what is wrong

the sender unit in the tank has a 3 pin plug with (obviously) 3 wires:

Blue 65 : Fuel Guage power wire

White 65A: Low Fuel Warning Lamp wire

Green/Yellow M66: Earth wire

 

the wiring diagram shows the 65 and 65A wires go direct from tank sender unit to the dash binicle

and the earth runs straight to the LR earth cluster

so far I checked the Left Rear earth cluster which is like new

checked for continuity of the M66 earth wire and its good

checked the fuse in the fusebox (No.2 , 25A) and its fine

with ignition on:

using the female loom plug at the tank, I completed the circuit by connecting a small wire from 65 to M66Earth - no movement on the dash Fuel Guage needle

same but connecting 65A to M66 with the wire - straight away my Low Fuel Warning Lamp came on the dash

 

Im already on my second Fuel Tank Level sender unit, as I took out the whole original tank and replaced it

the current tank's sender unit was working well previously before being put into the current car

 

is it possible to remove and fix a dicky Level Sender unit ?

and is there a tool to remove the screw in sender unit ? rather not bash on the tabs with a drift until they break off ..

 

cheers for any suggestions

 

 

 

 

 

 

[Gohn 68]

update, got the fuel level sender unit out of the tank

used a piece of PECS pipe and a small hammer to tap on the tabs of the screw-in black ring, WD40 and outsies

its black ring, level sender unit, then between that and the tank is a rubber sealing ring with 3 ridges

 

the sender unit is JAEGER

seems to be crimp sealed, 3 crimps around the top of the ally tube fixing it to the plastic top/3 pin plug

feels like a float slides up and down with the fuel level which enters the tube via a small hole in the bottom

 

the unit part number is #152796 but no longer available from Peug

so wondering if any tinkerers have ever drilled out the 3 crimps, taken off the ally tube and tried to fix the resister inside somehow ?

 

[Ozymandis 97]

Good morning, I have had the relavent multiplug not quite pushed home in the instrument panel on more than one occassion, I think its the top left hand plug.

 

If Your completing the circuit at the sender`s plug and the gauge doesnt move it isnt the sender unit at fault.

 

I have fixed a few senders, theres more than one manufacturer,  they were the type with a circlip at the bottom of the alloy tube holding them all together, they have a big bronze alloy coil like a slinky spring inside, it eventually snaps where its anchored at the top, its an easy fix if You can solder I have done it at the side of the road with a plumbers equipment on one occassion. Not sure whats inside a crimped one, probably a similar idea.

 

 

 

Edited March 30, 2021 by Ozymandis

[Gohn 68]

thanks jay,

I've just got the other one out of the tank

this ones a Veglia and as you describe,

haven't had the bottom circlip off yet because I doubt its the sender

I have now tried both level sender units plugged in with ignition on

tilt the unit up, tilt down, needle on the dash just wont budge a bit

glad to hear you reckon its not the sender unit cause I was thinkin it would be too unlucky to have 2 dudd units in a row

 

checked the top left binicle plug already, it looks pretty snug but took it off/on to see if that made a difference

nothin though

 

also, I thought it could have been the loom was being crushed/earthing between tank and body but it looks fine too

could it be the cluster ?

i've had them off/apart a few times before but where do look for a fault ?

 

 

 

[Gohn 68]

with ignition on:

just tested the power from the dash to the female level sender unit plug at the tank

I get 12volts for the low fuel level warning light (wire 65A)

and 6volts for the fuel guage (wire 65)

 

4 hours ago, Ozymandis said:

If Your completing the circuit at the sender`s plug and the gauge doesnt move it isnt the sender unit at fault.

could you explain this ? I dont understand

is the maximum resistance in an EMPTY or FULL sender unit ?

 

thanks again

[Ozymandis 97]

Empty is max resistance,  so not a lot of juice gets to the gauge,and it doesn't move very far up the scale.

Whereas if you short the plug terminals a lot of juice gets to the gauge and if gives full scale deflection of the needle.

 

Check the earth wire for continuity to the plug, i think its other end is in the rear wing earth block.

 

6V isn't right I`d investigate that after the earth wire.

 

i just drank a bottle of vino with my dinner so its all a bit hazy recollection at the mo.

 

[Gohn 68]

thanks jay, best not get in one of your fleet of 205's just now then,

 

I've already checked the earth, the plug to the level sender, the plug to the cluster, the loom wires (n evry feckin other thing)

so, I took out the cluster/binicle and put in another one

connected all the plugs at the back of the cluster 

 again, went to the tank and got the female level sender plug

put a wire across from Fuel Guage Blue65 to M66Earth to complete the fuel guage circuit with zero resistance

BINGO, the fuel guage needle goes to FULL !!

 

I have officially got a f***ed cluster, or what I prefer to call a Cluster f***

also proves your "Empty is Max Resistance"

 

spose Im gunna have to take the cluster apart, see if I can find the bad connection or whatever it is

 

 

 

[Gohn 68]

put the fuel level sender all back in tank, took out my cluster for inspection and ...found the cause of my CLUSTER FECK

 

a lizard had got into the cluster (probly thru one of the obsolete bulb holes) and made a bit of a mess, and laid a frikkin egg

so the extra moisture has corroded the fuel needle somewhat, (you can see it on the back of the right one)

dont know yet if the needle's siezed or the corrosion has effected the copper resistor thing that is at the back of the needle facia

had a spare cluster so have just unbolted and lifted out the dud fuel needle panel and put in the replacement one

once the clear plastic panel is off the cluster, to get the fuel panel off its two screws at the front (M5 spanner)

and three nuts at the back (M5.5 spanner), which each have a little ally washer for contacting the circuit sheet

put it all back together and slotted in and boom, needle reading just below half

 

crikey

 

[Ozymandis 97]

WTF, thats a new one on me!

 

We dont get many reptiles in Yorkshire apart from the odd smarmy politician from down South.

 

It must be the time of year, our turtle laid a clutch of eggs last week.

[Gohn 68]

just pleased its all working good

 

well, cept for the tacho

diesels and tachos dont get along real well

got a new part to try though, so here goes again for the umpteenth time