I hope someone out there will have some info to help me out. I would like to add a low fuel level warning light to my 72 B body rally gauge cluster. I have been looking for a factory relay with no luck,and was hoping that I could build one with parts from Radio Shack. Does anyone have a schematic of the circuit in the factory relay? (Or a lead to a factory unit at a reasonable price?) Thanks!

I have a spare one from an AMC Gremlin. It has a pentastar and a non-AMC part number on it. Pretty sure AMC sourced it from Chrysler. I'll see if I can dig it out. Couldn't tell you if it works or not though.

Weren't the low fuel lights in the overhead console on SE's? Never heard of one being in the gauge cluster.

The A02 driver aid group was an option on 71 GTX and Road Runners. The indicator light was located on the plate with the map light under the dash pad. I have this option on my RR. The relay is similar to the ones used on Gran Coupes, SE Challengers and a lot of C bodies, only difference was the mounting bracket.

I'm customizing a bit, so original parts/#'s don't matter, as long as it works! I want to put some yellow LED's around the gauge(hidden by the bezel) that will light up for low fuel.

the gauage was powered from the LFR ( low fuel relay) of the 5 volts-not from the existing one from the rest of the guages- the sender went into the LFR- there was a bit of electronics inside it.

so when the tank was around 1/4 full a circuit would turn on a relay inside and turn on the bulb.

That's pretty cool. Does anybody have a pic of the relay itself? I'd like to compare it to my AMC ones.

must to say IT WON'T WORK on 72 and lates UNLESS use plastic sockets kind ( some models had it with two blue wires ) to bulbs what makes a diff wires setup arriving to panel ( what doesn't exist, would be a custom harness )

WHY ? because on 71s, both lights are switched on by positive, for a while since 72 the seatbelt light is switched by negative and fuel light ( if existant ) will still be switched by positive.

Using the same metal housing where one wire is used by both lights and one wire metal sockets ( due being a common signal by chassis ) will short the panel on 72 and lates setup

Already analized all the system, and even I could make it to work ( got offered one complete setup, but I couldn't afford the price ) got that conclusion

would need to use plastic sockets and rewiring both to make it work safe, sending the correct signals to each bulb, isolating the sockets/bulb housing from any kind of information ( positive or negative )

NachoRT74-Is that relay mounted on the side of the glove box liner? Screwed in?

yes... screws going through the liner from inside the box

same piece what charger440sixpak is showing

as stated, YOU CAN MOUNT THEM DIRECTLY ON A 72 AND LATE without pay attention on some wiring mods going to sockets, and replace AT LEAST one of the sockets for the plastic one. Better if replacing both

OK! I found my spare one. Had one NOS that I plan to use, and one used one.

Here's pics:

Pic 2: They are very similar. Almost guarantee it's the same part.

it is in fact same piece, just diff body application so the diff bracket to diff mounting down the dash... same as practically every electrical piece around