Fuel low light always on [Archive] - SaabCentral Forums

: Fuel low light always on


JimmyG
28-02-08, 10:35 AM
I tried searching the forums but the search is again broken for me!

anyways. my fuel low light is always on in my 1991 C900T

i cant find anything in bently, where are the grounds for the fuel system? or which wires which so i can trace it!

otherwise a certain bulb is getting pulled in the dash....:roll:

16saabs
28-02-08, 03:08 PM
might be the fuel sensor/sender in the tank and it has got stuck,
my fuel dial/sensor relays a full tank fill up after about 4-5 mins,
it was laid up for 3 1/2 yrs(at one time, by p.o.)and I have been using it for nearly 2 yrs, so I expect it got a bit rusty/sticky on the sender shaft and that causes it to react slowly, even after the fill up the yellow light stays on for 1/4 mile,
I believe if you remove sender from tank and shake it up and down , you can hear the sender moving on the shaft, no noise would indicate sticky/rusty shaft?

900t
28-02-08, 06:11 PM
I tried searching the forums but the search is again broken for me!

anyways. my fuel low light is always on in my 1991 C900T

i cant find anything in bently, where are the grounds for the fuel system? or which wires which so i can trace it!

otherwise a certain bulb is getting pulled in the dash....:roll:

The thing for the light is seperate from the level sender... if you go to the sender you have like 3 wires... perhaps the wire is shorting and making the light.

Rodentmaster
28-02-08, 06:12 PM
The sensor for the Low Fuel light is.....

magnetic in the later fuel senders.
The sender has a thin aluminium shaft mounted in parallel with the main float shaft. The float rides up and down in line with the shafts. The small shaft has a small reed switch mounted in the bottom end.

There is a small magnet in the float of the sender. When the float approaches the lower point of the shaft, the magnet nears the reed switch and closes the circuit to turn the light on.

My Low Fuel lamp was on for the last year or so. I took it all apart and let it dry out. I unsoldered the wires and removed the reed switch. It is 'sealed' into the plastic body but I believe, while still locked into the holder, the glue has aged enough to allow a small amount of movement which has either allowed the contacts to short prematurely or fuel getting in has changed or made the switch sticky.

While apart, I apllied a healthy amount of supaglue to the body to help stabilise the wires coming out of the reed switch.
Re-assembled and has been working well for the last 6 months.