1967 Low Fuel Light - Team Camaro Tech
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post #1 of 13 (permalink) Old Nov 9th, 17, 06:21 AM Thread Starter
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Michael
 
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1967 Low Fuel Light

I have owned 5 1967 SS/RS Camaros with U17 (gauges), and none of them had an operational low fuel light. The last one I have, my wife's SS 350, has the problem and I'd like to get it working.

As part of this car's ongoing resurrection (over the years), all the wiring harnesses have been replaced and I noticed the little plug in light socket at the end of the yellow wire behind the speedometer. The old original harness just had a snipped yellow wire. For years, I just left the light unplugged until about a year ago when I plugged it into the FUEL socket. Shortly thereafter, my tach stopped working as well as my BRAKE indicator. The car is no longer a daily driver, so I only investigated the issue yesterday to find that my original printed circuit had melted/separated in 2 places along the lower edge.

Apparently, the light tried to work (I have a low fuel module connected to the fuel gauge in the console) and it fried the printed circuit and blew the 10 amp instrument gauges fuse. This is when I really started doing some research to get this thing working.

I looked up the U17 part in the 67 AIM and there isn't a description of plugging the yellow low fuel light into the dash cluster (there's a great description of wiring the low fuel module in the console though). And from what I've read here on this website, the 67 module sends a positive signal to light the indicator while 68 and 69 send a negative.

I don't know what happened, but I'd like to understand it.

The low fuel plug-in light isn't the half twist kind like the rest of the dash lights, it's the press in type like the illumination lights in the console. It's apparently meant to ground into the dash cluster and receive the positive signal from the low fuel module to light, but that socket is the same as the other sockets on the printed circuit; in that it's built with the twist-in contacts which don't allow the socket to ground. I was thinking that the AIM would advise modifying the printed circuit (cut away the plastic) for that use, but there is nothing.

I'm getting another printed circuit and rather than cut the plastic away, I'm going to use a twist-in light. The low fuel light is on a short pig-tail connector that I removed and replaced with a short dash connector in the number 8 position (I harvested the connector from my old original harness, waste not want not).

I must confess that I don't actually know if my low fuel module is a 67 or other at this point, but I'll test it with a multi-meter to make sure.

Why isn't this part of the 1967 U17 AIM?
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post #2 of 13 (permalink) Old Nov 9th, 17, 11:37 AM
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Re: 1967 Low Fuel Light

Light, by design, comes on at approx 3 gallons remaining.
Box is a semi-conductor, meaning you could take the DMM leads, with meter in diode position, and measure front/back resistance.
Should be greater than 10 times between front to back measurement and box disconnected, on workbench.
New bulb may be too much load for semi-conductor, might need to find OE bulb.
Schematic here.
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post #3 of 13 (permalink) Old Nov 9th, 17, 12:45 PM
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Re: 1967 Low Fuel Light

My 67 low fuel light socket that plugs into the dash cluster is under the circuit board, not over it, and the yellow wire comes through the circuit board opening. Maybe that is why you have a short now?

Mike

67 LOS SS/RS L35 Hardtop - Original w/UOIT
67 NOR SS/RS L35 Convertible - Restored
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post #4 of 13 (permalink) Old Nov 9th, 17, 03:19 PM Thread Starter
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Re: 1967 Low Fuel Light

Mike_S,

That makes sense, that's probably why the yellow low fuel light socket has a short pig-tail. First you plug in the low fuel light, then you overlay the circuit with the yellow pig-tail poking through the opening.

I wish the AIM reflected this.

I now have 2 solutions depending on whether the module signal is positive (67 style) or negative (68-69 style). If it's positive, I'll fit the original light under the printed circuit, for negative I'll use my twist-in socket solution.

Thanks.
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post #5 of 13 (permalink) Old Nov 9th, 17, 03:25 PM
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Re: 1967 Low Fuel Light

When I had to change the low fuel lamp I was surprised of that design. It certainly looks like an afterthought. I found it easier to remove the dash cluster to change the lamp because the circuit membrane is so delicate and I didn't want to risk tearing it by that area.

Mike

67 LOS SS/RS L35 Hardtop - Original w/UOIT
67 NOR SS/RS L35 Convertible - Restored
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post #6 of 13 (permalink) Old Nov 15th, 17, 02:08 PM Thread Starter
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Re: 1967 Low Fuel Light

Well that didn't last long.

After reassembling my dash with another printed circuit and installing the low fuel lamp as Mike_S mentioned, I felt confident that everything would be fine. I started the car and lo and behold, the FUEL light lit because I had less than 1/8 tank of gas (or so my gas gauge indicated) and I thought I was home free.

The next day I decided to drive to get some gas and see if the light would go out with a half tank of gas. I never made it to the gas station.

After about 5 minutes of driving, smoke began to emerge from the front of my console and the FUEL light began to flicker. I stopped and disconnected the big console harness plug from the dash harness and drove home hoping nothing major happened.

When I got home and removed the console I found that the low fuel module had split (from heat) and the red and green wires were melted. I'm glad I went home as the hot wires put a pin hole in the oil pressure line. Peachy.

Back to square one.

Amazingly, I found the aftermarket low fuel module's original packaging and instructions (it's been a few years) and I checked the wiring. Red to pink, green to tan, black to ground and yellow to the low fuel light. Some folks might want to take note of the wiring as the 67 AIM doesn't say which color goes where.

I also found my original low fuel module and put it back in place. With the fuel still at an eighth of a tank, it still doesn't light the FUEL light, but at least it didn't melt down.

I'm planning on giving up (not a big fan of car fires), but I have one last question. Is there supposed to be a flat resistor between the 2 fuel gauge leads?

Thanks.
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post #7 of 13 (permalink) Old Nov 15th, 17, 02:45 PM
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Re: 1967 Low Fuel Light

Mike, the schematics for the console and gauge package is in the 1967-69 CAMARO RS CONSOLE GAUGE & HEADLIGHT WIRING DIAGRAM MANUAL.

Ed


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post #8 of 13 (permalink) Old Nov 15th, 17, 04:12 PM
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Re: 1967 Low Fuel Light

I dunno how accurate any of this is, but mine don't come on until the gauge reads E, not a hair over. I honestly didn't think it worked until recently when started it after setting for a spell. Then after putting in gear and moving, the light went out.

  • '68 RS, AA, 749, L30, M(uncie)20 (originally a 3spd), 15yr backburner resto........
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post #9 of 13 (permalink) Old Nov 15th, 17, 04:54 PM
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Re: 1967 Low Fuel Light

Hi Mike,

My lamp doesn't come on until the gauge is near E. I figured there is maybe one usable gallon left.
Attached are two pictures I took when the car was apart for restoration. I marked one with red, green and yellow arrows to point to the three wires.
There is also a flat wire wound resistor between the gauge terminals.

Mike
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67 LOS SS/RS L35 Hardtop - Original w/UOIT
67 NOR SS/RS L35 Convertible - Restored
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post #10 of 13 (permalink) Old Nov 15th, 17, 05:33 PM Thread Starter
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Re: 1967 Low Fuel Light

Mike_S,

My low fuel module is wired the same and I have the flat resistor too (thanks for confirming).

I don't know if my original module works, but I guess I'll have to drive the car a few times to get the fuel gauge closer to E.

I sure hope nothing catches fire.

Thanks.
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post #11 of 13 (permalink) Old Dec 7th, 17, 10:35 PM Thread Starter
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Michael
 
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Re: 1967 Low Fuel Light

Well I had another crack at my low fuel warning light while putting my original AM radio back into service.

After my aftermarket 67 style (positive output) LFW module went up in smoke, I found one of the other LFW modules I've collected over the years. The one I grabbed first had thinner wires than the 67 and proved to be a 68.

I swapped out the 67 module for the thinner wire module and promptly shorted out my fuel gauge sender in the trunk so that the fuel gauge would read empty. With my instrument cluster removed, I tested the yellow LFW lead for positive or negative. It turned out to be negative (yea!) and I verified by "grounding" the 67 style LFW pigtail light socket to the double pink lead (+. position 9 on the cluster connector) and was rewarded with illumination.

Previously, I rigged up a replacement for the LFW light that uses position 8 (like on a 68 instrument cluster with LFW) and twisted a new cluster light in the LFW hole. I put the whole thing back together and it works perfectly when the fuel gauge sender is grounded. I still have about a eighth of a tank, so I have a little driving to do before the light comes on by itself.

Finally.
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post #12 of 13 (permalink) Old Dec 8th, 17, 05:42 AM
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Re: 1967 Low Fuel Light

My Low Fuel Light starts to flicker as the fuel sloshes around in the tank. I have a replacement aftermarket module with an original fuel gauge. Sometimes when I'm doing some spirited turns the light will flicker when I have more than a half a tank. It will stay on steady when I get to 1/8 tank. So mine starts warning me long before I need to stop for gas.

Brian

'67 SS/RS 350, Muncie M20, Black with black interior.

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post #13 of 13 (permalink) Old Dec 8th, 17, 08:17 AM
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Re: 1967 Low Fuel Light

my 69 low fuel worked great. It started to flash with gas sloshing around at apox 1/4 left in tank, it went sold red at about 1/8 gallon left in tank.

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