plummo_vtec

hi there guys, i seem to have trouble with the low fuel warning light it doesnt illuminate any more the guage works fine but the light does not come on any more i know it is not the bulb as i have checked can anyone help me out

crazyguy

to change the bulb in cluster takes a bit time cause u have to tear down the bazel,and take out cluster, my fuel warning light does not work either.but it does not bother me. i suppose to pump the gas when it is low, dont need the fuel light to remind me to get gas. but it is just me.
if u want to take out the cluster.and dont know how to . pm me

hondateg10

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crazyguy &raquo;</TD></TR><TR><TD CLASS="quote">to change the bulb in cluster takes a bit time cause u have to tear down the bazel,and take out cluster</TD></TR></TABLE>

WOW! you are doing it the hard way to get the bulb out. just take the cluster out and on the back are the bulb holders twist and the bulb comes out. 10 mins at the most

crazyguy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondateg10 &raquo;</TD></TR><TR><TD CLASS="quote">

WOW! you are doing it the hard way to get the bulb out. just take the cluster out and on the back are the bulb holders twist and the bulb comes out. 10 mins at the most
</TD></TR></TABLE>
sorry to mention. thats what i did for my eg civic

plummo_vtec

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crazyguy &raquo;</TD></TR><TR><TD CLASS="quote">to change the bulb in cluster takes a bit time cause u have to tear down the bazel,and take out cluster, my fuel warning light does not work either.but it does not bother me. i suppose to pump the gas when it is low, dont need the fuel light to remind me to get gas. but it is just me.
if u want to take out the cluster.and dont know how to . pm me </TD></TR></TABLE>


QUOTE "the light does not come on any more i know it is not the bulb"

why are you telling me to change the bulb when i have already said it is NOT the bulb

hondateg10

sry man. you might have a bad connection from your sender unit

Kuchtaboy

but if the meter is still working, why would the sender unit be bad?

Former User

There is a separate component associated with the sending unit that controls the fuel warning light.

Kuchtaboy

didn't know that. Just figured when the strip it the right resistance it just tripped the light.

good info.

Former User

By the way, here's the circuit diagram showing that the fuel warning light is controlled by a separate sensor:

Kuchtaboy

lol, from that diagram it looks like it's the same sensor unit... What it looks like is when the sending unit bottoms out from the fuel level it cuts the flow of electricity and forces it thru the indicator light...... like I said.

Someone correct me if I'm wrong.

I think you should find that Green/Yellow wire and look for a break in the line

Former User

I agree that looking for an open in the GRN/YEL wire would be a good idea; however, like I said, the diagram clearly shows that the fuel warning light is controlled by its own sensor in the fuel unit, which also happens to contain the fuel gauge sending unit. Therefore, you could have a fuel gauge that works fine but the warning light doesn't because the warning light sensor is bad.

Kuchtaboy

do you understand how the sensor works tho? There's 2 powers coming into the unit.

I doubt you can just get that sensor, if it even is an actual sensor. I think it's just a solid wire with a resistor that's higher then the resisitance of the sending unit. forcing the electricity to flow thru that wire triggering the light.

It's not an actual sensor, its a resisitor

Former User

Of course, sensor is simply used as a general term. I never said you would be able to replace only the warning light sensor/thermistor if it happens to be bad. In fact, the diagram suggests that the whole fuel unit would need to be replaced. I informed you that a bad warning light sensor could possibly explain your observation that the fuel gauge works but the warning light doesn't. I stand by this claim. I'm sorry if you misunderstood my comments.

Also, based on the circuit diagram, my guess for how the sending unit and warning light circuits interface is:

1) A low fuel reading by the tank float increases the resistance in the sending unit's variable resistor, thereby generating heat.

2) When sufficient heat is generated by a nearly empty tank, the adjacent thermistor is triggered to reduce electrical resistance in the warning light circuit, thereby permitting current flow that turns the warning light ON.

Modified by RonJ@HT at 12:41 PM 3/5/2008


Modified by RonJ@HT at 12:58 PM 3/5/2008

plummo_vtec

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RonJ@HT &raquo;</TD></TR><TR><TD CLASS="quote">Of course, sensor is simply used as a general term. I never said you would be able to replace only the warning light sensor/thermistor if it happens to be bad. In fact, the diagram suggests that the whole fuel unit would need to be replaced. I informed you that a bad warning light sensor could possibly explain your observation that the fuel gauge works but the warning light doesn't. I stand by this claim. I'm sorry if you misunderstood my comments.

Also, based on the circuit diagram, my guess for how the sending unit and warning light circuits interface is:

1) A low fuel reading by the tank float increases the resistance in the sending unit's variable resistor, thereby generating heat.

2) When sufficient heat is generated by a nearly empty tank, the adjacent thermistor is triggered to reduce electrical resistance in the warning light circuit, thereby permitting current flow that turns the warning light ON.

Modified by RonJ@HT at 12:41 PM 3/5/2008


Modified by RonJ@HT at 12:58 PM 3/5/2008</TD></TR></TABLE>

so i guess you are saying that the whole thing could be kaput and needs changing

HYBRDcrx

Yes, that is what he is saying. RonJaht, the unit isn't acuated by heat, heat is generated but energy takes the path of the least resistance. So you are right when the variable resistor is high the low fuel light illuminates because the power is taking that path of the least resistance.

Former User

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HYBRDcrx &raquo;</TD></TR><TR><TD CLASS="quote">RonJaht, the unit isn't acuated by heat, heat is generated but energy takes the path of the least resistance. So you are right when the variable resistor is high the low fuel light illuminates because the power is taking that path of the least resistance. </TD></TR></TABLE>

The weakness of this conclusion is that the circuit diagram indicates that the fuel warning light "sensor" is a thermistor (heat activated) rather than a simple resistor.


plummo_vtec: If you have verified that the GRN/YEL wire does not have an open (as suggested by Kuchtaboy), then replacing the fuel unit (shown in the circuit diagram) should fix your fuel warning light problem.


Modified by RonJ@HT at 8:10 AM 3/8/2008

cachase1

In the del Sol, there are two wires. When I first got it, the fuel gauge didn't work, but the light did come on when it got too low. Turns out that all of the wires going to the fuel pump were being cut by the 'personal compartments' behind the seats. Someone took it out and didn't move the wires out of the way before reinstalling it. All of the wires were either cut or arcing out on other wires where the metal was exposed.
I would say, first check for continuity between both ends of the Green/Yellow wire. If you can rule that out, then your problem is probably in the sending unit itself since the bulb is functional.

Chris Chase
'02 Accord LX
'96 del Sol S

Seahawk

Not to detour this thread

Did the 1994 Civic Hatchback VX have a low fuel light?