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dull lighting

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jayc1945 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jayc1945 Quote  Post ReplyReply Direct Link To This Post Topic: dull lighting
    Posted: May/02/2021 at 8:30am
hey folks, my 68 amx seems to have dull lighting on everything, dash, parking,turn sig. the alt. was rebuilt before i bought it , the headlights seem to fluctuate when idling. could this be a ground prob? or could i remedy w/led lights? any info would be great! 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2021 at 9:02am
What is your battery voltage? That will determine if you have a charging problem. Measure directly across the battery terminals. With the engine off you should see 12.6V. With the engine on it should be over 13V. Alternators have a "stall" speed, so rev'ing the engine up a couple of times will help engage the charging system.

When you say the lights are dull, what are your expectations? Automotive lighting technology has improved a lot since 1968. It will not be as bright as today's vehicles. That said, there are things that can be done to help. Clean all the bulbs and lenses. If the lenses have clouded through time, try buffing them out.

The back lighting in the instrument cluster uses green plastic hoods to give the dash that glow. They collect dust over the years which dims the light output. Cleaning them will help. You will need to pull the cluster and open it up to do this.

LED bulbs can help, but they're not all created equal. If you do and advanced search in the section using the search term "LED", you find many threads by members who have done LED conversions. Two caveats to be aware of, if you change the signal lights to LED, they will flash at a different rate. Also, if you change the cluster lighting to LED, the dimmer on the headlight switch won't work properly. There are solutions, just read through the threads.
69 Javelin SST BBO 390 T10
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68-73 amx View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 68-73 amx Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2021 at 10:49am
When I cleaned my bulkhead connector ( took out old dielectric grease , cleaned and tightened electrical connectors , replaced dielectric grease ) lights everywhere were much brighter. Might be worth a try.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2021 at 2:50pm
That's good advice if there is a bulkhead connector on the firewall. A 68 AMX doesn't have one. The harness passes through a grommet on the bulkhead plate. It wouldn't hurt to check the other connectors for corrosion though.
69 Javelin SST BBO 390 T10
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 68-73 amx Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2021 at 9:41pm
Got me on a technicality..Shocked
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: May/03/2021 at 6:20am
There is a grounding tab on the headlight switch, IIRC. Make sure it's there for one thing (I think it is removable?), then make sure it has good contact (or run a ground wire to the switch).

I'm not that up on the Javelin/AMX, but do recall reading here on the forum about that. May only apply to the "hump fender" 71-74 models though -- they have a different dash, obviously. Hopefully someone more familiar will chime in here!

On any car, you can install relays for the headlights that will usually make them brighter. Will also increase the life of the switch. The switch just activate the relay and has far less power going through it to do that. Relay powers headlights from battery. Doesn't help your other lights -- which is why I believe you have a ground problem at the switch, or a worn switch.
Frank Swygert
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george w View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote george w Quote  Post ReplyReply Direct Link To This Post Posted: May/03/2021 at 9:03pm
The ground lug on the headlight switch is there to provide the ground for the interior lights when the knob is turned fully CCW past the detent. This is the only purpose for the switch to be grounded as the dash structure is plastic.
The OEM headlights, if you still have them, were not that bright even when new. Halogen replacements, like Sylvania Xtravisions are noticeably brighter but still not up to modern standards.
You do want to make sure your battery cables are good, the connections are clean not only at the battery but also where the positive connects to the starter relay and where the negative attaches to the block.
The main feed for the car body power is the heavy wire in the main harness that connects with the battery positive cable on the starter relay.
Ground for all body circuits is provided by the jumper wire by the passenger side of the engine block to the cross member. This has got to be solid and clean as well.   
Long time AMC fan. Ambassador 343, AMX 390, Hornet 360, Spirit 304 and Javelin 390. All but javelin bought new.
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