View Full Version : relay

08-03-2005, 04:31 PM
Could some one tell me where i could purchase a fuel gage relay for a 1970 Javelin. It is located under the dash below the tach. Manufactured by Chrysler . I have tried quite a few places with out any luck.
Thanks Naglehead

Vegas dude
08-03-2005, 05:16 PM
I am curious - Is this why so many Javelins and AMXs for sale say "gas guage does not work, but replacing the sending unit is easy?" Is it really the relay that could be bad?

08-04-2005, 02:03 PM
In my case it is the relay. So if you have one let's do some swapping.
Thanks ia

08-05-2005, 08:45 AM
The only relay that I am aware of for the Javelins and AMX's are the low fuel relay that is located just above the steering wheel on the right side. These relays can be bypassed and the fuel gauges will then work. The sending units can be changed however I guess they are AMC specific and a GM or Chrysler sending unit will not work on them (Could be wrong on this one, going by what I was told). The low fuel relay are kind of the devil to get operating correctly onced they go bad and most will go bad due to age. Will try to find the info to pass along on how to disconnect the relay.

08-10-2005, 02:18 PM
This relay or resitor not sure what it is called has four spades coming out the back. One is ignition .one is comon. One is gauge. and one is lamp. Took it apart and found the tiny hair like wires were broken. It also has a what appears to be a very small wound coil or resitor . Maybe this will shed some light or ring a bell as to what the proper name is. Any help would be welcomed

08-10-2005, 05:03 PM
There should be a yellow wire that goes to the relay (plugs in). Take that yellow wire and connect it directly to the gauge. Unwire the relay totally and disconnect the wiring that goes to it. This may require that you have to totally remove the dash panel to gain access to all of the wires. The yellow wire is the active wire that goes to the fuel sending unit via the pin setup on the back of the dash panel. Next test the wire on the sending unit. If you use a voltmeter, it should read around 5.5 volts (give or take a little) or if you use a test light, it should pulsate dimly the bulb on the test light. The fuel gauge itself is wired though the voltage regulator that is located on the back side of the dash panel assembly. Kind of complicated, but fairly easy once you have done it once. Have some fun and try to save your originial fuel gauge. Any futher problems let me know and I will try to help.

10-08-2005, 06:06 AM
With my 1970 Low fuel indicator,I noticed that the actual light bulb is unique. It looks like a regular dash bulb, but it is actually a special 'flashing' bulb. I can't remember the actual bulb numbers, but I remember finding a listing for it in one of my old parts catalogs, I think it was a numerically small number (like '41'?), but physically looked like a typical dash type bulb(1845?). I seen two different cars (one had the wrong bulb,other the bulb was burned out) fixed by this. The only place I have found these special bulbs have been off parts cars.
Does someone have the schematic for the low fuel option that they could post? I thought I saw a website with a tech tip on this subject somewhere? :confused:
Maybe I am just by-passing some other problem with these 'magic' bulbs? :o

charles maxwell
04-18-2006, 05:53 PM
I have a 70 AMX and cannot get the temperature or fuel gauges to work. Could it be the instrument gauge regulator? I have tried everything and get no movement at all in the gauges. I have already disconnected the lo fuel light as I read that it causes many problems. Any help would be appreciated. Is there a way to check to see if this regulator is faulty?

charles maxwell
04-20-2006, 10:44 AM
Could some one tell me where i could purchase a fuel gage relay for a 1970 Javelin. It is located under the dash below the tach. Manufactured by Chrysler . I have tried quite a few places with out any luck.
Thanks Naglehead
Dids yoy have any success findiing a relay. I am having the same problem with my 70 AMX. Let me know if you found the part and where. Thanks!Charles Maxwell

03-12-2007, 07:02 PM
Copied and paste this from CaliforniaClassics: Hope this is ok
Fuel Gauge Problems

Troubleshooting 68/70 Fuel Gauge Problems.

If your gas gauge was working OK, but all of a sudden it quits working altogether, or the needle is reading LOWER than the amount of gas that is really in the tank, then this is the fix for you. 68/70 AMX and Javelin fuel gauge test. This will be a process of elimination. Let's start with the gauge itself.

Put the car on jack stands and let the rear suspension hang down. Remove the passenger rear wheel. Doing this will give you plenty of access to the fuel tank sending unit. First things first. Is the yellow feed wire connected to the sending unit? If not, make sure the terminal on the sending unit is clean, also make sure the yellow wire socket is clean and that it fits tightly on the sending unit terminal. Check the sending unit black ground wire. Make sure it is clean and connected. Turn the key on and check the gauge. If it still doesn't work, then try this next test. Remove the yellow feed wire from the sending unit. Do not remove the ground wire! Find yourself a 5 to 6 foot long jumper wire the same gauge as the yellow sending unit wire, and strip both ends of the jumper back about 1/2 an inch. Take one end of the jumper wire and push it into the yellow feed wire socket. Bring the other end over to the driver side of the car. Sit in the car, turn the ignition to the "ON" position and touch the end of the wire to any one of the scuff plate screws. What you're doing is "grounding the gauge". If the needle goes all the way past "full", then the problem IS NOT the gauge. if the needle doesn't move at all, then the problem is in the feed wire from the gauge to the sending unit. Here's where it gets interesting. In 70 there was an option known as a "low fuel warning system". It was designed to warn the driver when the fuel level gets to 1/4 of a tank or less. When the fuel level gets to 1/4 tank, a light flashes in the center of the fuel gauge. If you have this system in the car, then chances are this is the reason why your gas gauge won't read at all. If you have a 68 car, or if you don't have the low fuel system in your 69 or 70, then the problem IS the sending unit in the gas tank. (usually the float, or a burned out unit all together) To determine whether or not you have a low fuel warning system, look closely at the face of the fuel gauge. Between the "F" and the "E" will be what looks like a tiny rectangle slot. If you see this slot, you have a low fuel system. It operates off of a relay located under the dash directly right of the steering column, secured to the dash frame with one screw. It has a 4-wire plug off the relay that connects to the back of the instrument cluster circuit board. It is not enough to simply unplug the relay and solve the problem. You MUST COMPLETELY REMOVE the 4-wire harness from the back of the circuit board. The key to doing this correctly is dependent on the orange light wire which is part of this 4-wire harness. Notice how the orange light wire is plugged into a black plastic socket? The socket is held onto the circuit board by one of the nuts that holds the fuel gauge into the cluster. Remove the nut and take off the socket. Make sure you put the nut back on and snug it down! By doing this you have reconnected the original circuit, only without the low fuel system. Put your cluster back in and make sure your main harness plug in connected. Turn the key on and check the gauge. If it works, then your problem was a burned out low\ fuel relay. If you don't want to go searching for an NOS replacement relay (used relays are not reliable, nor are they accurate) then just put you dash back together and leave it alone. Even when the low fuel system is working correctly, it can be a real annoyance as the light will continue to blink until you decide to fill the tank. I believe this was really designed for long trips where you don't pay a whole lot of attention to the gauge as you're cruising along, and starts to blink when you're low on gas, or reminds you to wake up and go get some gas! I hope this helps answer questions on this subject. As you can see, these are fairly simple tests to tell you EXACTLY where the problem is and how to fix it. Good luck!

For more information on these, or any other AMC related subject, don't hesitate to give me a call.

Tony Zamisch

California Classic AMC, Inc.

(619) 423-0364