billschroeder5842

My 82 is equipped with a low fuel warning light in the center cluster. I found this out when I recently rebuilt the console electrical and found that the transistor was missing. I've since installed the bulb/transistor combo.

The way I understand how the light operates, is that the low fuel light "barely" comes on at some point and then progressively get brighter as the fuel level goes down, ultimately becoming fully lit.

Does anyone have any idea on what is "normal" for the light? My light comes on (barely) at about 1/3 tank. This feels a bit early to me but maybe not?

Anyone with experience?

hugie82

My 82 comes on with about 3-4 gallons left.

The13Bats

Both my 81's came on down past 1/4 lower than I would have liked but my memory doesn't recall the dim to bright thing you mention,

righthanddrive

My 79 came on at about 1/8 full at full brightness.
Willcox has a video on testing the module and it comes on full with no progression

mk's78

Hey CF gurus..Great post...I've had my 78 SA for several years and also would like to know if it has a low fuel indication? And about how low will it should get to begin to illuminate???

mk's78
mike

righthanddrive

It came as an option. Willcox has new ones for $58 part # 6432350. You may be able to install it by taking out your glove compartment. It twists in like a light bulb. My 79 had one that only worked about a dozen times before a resistor burned out. I managed to get ahold of the right people at GM and they gave me the part number for both of the resistors on the board in case the other one went bad.

The13Bats

On my first 81 the mod died and I knew this electronics geek, he would sit while talking to you and build a circuit for silly stuff like fm transmitters and weird sensors,

I ask him can you fix this, a test or two later and some soldering he says here, never failed again, he pulled the replacement parts from an old parts bin he had.
The system is just set to light at a certain ohm reading with added thought so it doesn't flash when taking fast turns etc.

Super cool willcox took on an aftermarket version but times change if a person wants to add generic low fuel light buzzer or both to older car it's easy and cheap

https://www.spiyda.com/magento/index...result/?q=fuel

billschroeder5842

Thanks everyone!

I'm going to mess with mine today and see if I can get it to read the correct way.

The bulb holder has 3 contact points on it; one at 3:00, 8:00 and 10:00 so two on one circuit and one on the other.

My thought is if I flip it 180 degrees I'll get a different (more accurate) reading?

From the posts it seems that the bulb should go on at something less than 1/4 and right about 1/8 which seem correct to me.

0Willcox Corvette

Actually the factory low fuel module came on at about 3 ohms resistance... Which to me was way to late so when we revisited this module years ago we increased it. Originally we made them just like GM with a few changes to keep them from blowing up... But we modified this a couple of years ago to come on right before the fuel gauge needle touches the red...

-Willcox

The13Bats

could a pot be added to make it adjustable or not worth it?

0Willcox Corvette

We could add an adjustable pot so you could trim it but it would be a pain... and an added expense.

It's really not worth it and the new design seems to make everyone happy. I can't tell you the ohms reading we have it set too, (privy info)... but it's higher than the GM setting so the customer gets a light at the red instead of 1/2 way into the red.

Ernie

The13Bats

the only person that ohm reading would help is a cat trying to rip your part,
I plan to get the generic one I linked to, it will support a buzzer led etc, it's adjustable but being generic has to be,

The stock one in my 81's came on too soon I thought...

On the subject of gauges and senders and carry over bashing import crap parts, do you see much variation in a sender, in other words if you had the same temp sender and tried it in 5 cars would the reading be the same or differ and if differ how much?

0Willcox Corvette

The car doesn't matter.. the themistor inside the sender is what controls the ohms output and it will react the same regardless of which car it's in. So one will read exactly the same from one car to another. It sucks that GM changed this in the early 90's and that all the aftermarket vendors followed suit. But to me the only good sender is a original sender.

In regards to the LFW module.. yes we've already had someone rip off the design but it's okay we changed it after the fact.

I can make one with a buzzer if that's what you want but I'm really not sure why you'd want a buzzer. A buzzer is very do-able but I'm not sure how people would like a buzzer going off for 10 minutes if they have a 10 mile run to the next exit.. I know it'd drive me nuts but to each their own.

Willcox

billschroeder5842

Well, I "flipped" the bulb/transistor and the (dim) light went out.

So either I installed it improperly or I need to run some more gas out of it and see if/when it pops on.

The13Bats

I love gadgets and geegaws, my 66 cockpit was a mix of digital, race and rat but it must have flowed some folks liked it,

My 69 will have several magic switches and idiot lights, electric doors etc it didn't come with low fuel but I dig that option, in road warrior max has a slow beating idiot lamp for low fuel and duded on the soundtrack is the idea it's pulse buzzing,
so that's why I want it in my 69 a small switch will kill the buzz.

Sorry Bill for the high jack but now you have a great excuse to go on a long fun sat night cruise to drain the tank....

mk's78

Interesting post..Can you tell me how I can tell if my 78 SA came with the low fuel indication option without letting the fuel run down to near empty???
mk's78 Mike

4SPDL81

'81 shop manual page 8C-9 states the following, "...the optional low fuel warning light comes on when fuel level drops to approximately 7.5L (two gallons)."...Good Luck!

billschroeder5842

4SPDL81-

Thanks for the lead--I checked my 82 shop manual (page 8C-9 none the less!) and it reads the same.

I'll run gas down some more and keep my fingers crossed.

0Willcox Corvette

It's easy to check, just follow the video and it'll show you. You run power to it, ground to it and then ground out the lower terminal... It should light in 10 seconds if working properly.

billschroeder5842

**UPDATE**
I ran gas down some more and the light came on just above the redline-- which is fine in my book. It also came on quickly and not the progression as I read.

Flipping the unit made the difference.

Thanks boys from Wilcox for the direction and help!