i have owned this 1974 scamp with automatic transmission, "225" engine, a/c, for about 2 months. when i first got it the lights on the left side of the panel including gauges would come on but were noticeably dim. about a week ago they all went dead. i'm guessing it's the light switch. the wiring has been spliced up pretty bad. they added what i'm guessing some sort of cheapie alarm system by "audiovox". it still sits under the hood, but the fuses have been pulled so i doubt that it works. i also have the remotes for it. i did check the fuse box and the fuses all look good, although the box itself is just dangling. i have also asked about a drop in rpms. in the "engine" section, i'm trying to work the bugs out being it's my daily driver. in that forum i describe all the work and parts i have done to and put on the car. i have also put all new light bulbs and their retainers on the panel to no avail. also, is the speedometer cable disconnected by simply squeezing the retainer clip? i can only move the panel out about an inch even with the cable disconnected from the transmission. thanks for your help.

There was an aftermarket radio/casette in my truck when I bought it three years ago. It would only work if the ignition was on. After I got a FSM, I started looking at the wiring diagrams, specifically the accessory circuit. When I finally went under the dash, I found the accessory plug near the parking break, but nothing in it. I followed the wires from the back of the radio to some odd shaped connector behind the ash tray. I stuck my head further under and found where it should have been plugged in. Just for SnG, I turned the key only to find a previously unknown seatbelt warning light, as well as the accompanying buzzer. I took the wire from the radio and ran it over to the accessory circuit. There was plenty of wire, so I can assume whoever installed it barely knew what they were doing.

I've seen similar messes with most of the TMC giveaway cars; in every case we removed the whole harness from the car. It is much easier to stretch it out than try to work up under the dash. While it is work to get it out, it saves a lot of grief in the long run. You can see our latest project at
http://www.tidewatermoparclub.com/tickets.html

Whether you decide to pull it all or not, it is **essential** you get the factory schematics; Chiltons or Haynes just aren't even close.

[I also strongly recommend you use the special vinyl wrap (NOT electrical tape) used to bundle the harness (Eastwood and YearOne and others carry it). I also suggest you get a good crimping tool, heat gun, heat shrink, uninsulated crimps, etc.]

The A bodys use a round female connector that pushes onto pins on the PC board in the back of the instrument cluster for most of the electrical connections except the ammeter, a few lights, and the switches. Those pins sometimes can work loose (especially if someone didn't push or pull the connector straight off and on) and make intermittant or poor contact. If your gauges work OK, the cluster ground is OK too.

A test light is a good way to see if power is getting to the connector, and to see if it's getting to the board.

The ammeter nuts often practically spot weld themselves in place, so I often use a Dremel tool w/ a #409 disk to cut the nuts off and preserve the shafts; putting too much torque on these nuts will break the ammeter studs free from the internals of the ammeter.

The speedometer cable clips can be a bear to get off; I believe '68-up went with the clips. If it's really hard to squeeze it, try to disconnect the trans or cruise control end and let the cable slide out with the cluster when you remove the cluster and then you'll be able to get at it easier.

K. Beard, a lot of good information. i am contemplating replacing the gauges with ones that are more precise. i did about everything you suggested except i didn't want to pull too hard on the panel. problem is i still couldn't see what i was doing. it still felt like it was hung up on something even with the cable detached from the transmission. i know the only way i'm going to get to the source of the problem is to pull the panel out to where i can work on it. also, i have the "original" two volume shop manual and i also have the tape. my thoughts are to read the schematic, follow one wire at a time and replace each wire back to the original set up. i will test the alarm system to see if it works, if not or if it's junk, it's history. i need to clean up the wiring, repair it as "new", and wrap and route it better than it is now. thanks for the information. by the way, nice car!

well, i have finally got the instrument panel off. i found one of the plug in connectors had a couple wires with bad corrosion. so i sanded them down and cleaned them off. i also found a fuseable link in the engine compartment right at the firewall (#10 red wire) connected to (i think) a relay next to the battery and in it's fried. i looked at the wiring diagram and i can't make it out. i also took the cheapie alarm out (being it was disconnected anyway, about 10 lbs. of wires). i need to know what that fuseable link goes to. if it's to my "engine idle solenoid" then maybe thats why my car drops so much in "drive". need help! thanks!

The relay near the battery is the starter relay; it is the central point for all the car's power. If the fusible link was fried, look at the pin on the blulkhead connector - it very likely was damaged by the current. That pin, and the two that come from the alternator (also with fusible links), are weak points that should be inspected for damage. Look for corrosion and melted plastic around them.

Some A-bodies have an unused pin space right next to the lead comming from the starter relay; in this year's TMC '75 Duster I ran a 2nd wire + link to it, and from there to the ammeter to parallel the factory system' battery side. The factory HD system just ran 10gauge wires through the bulkhead via a rubber plug to bypass the multipin connector and to straight to the ammeter.

The factory system is OK if everything is in good shape, but is succeptible to overheating due to a little corrosion or excessive current - beware of just dropping a much higher rated alternator. It would be a good idea to measure the voltage drops - if you see more than 0.5V I'd worry a little.

K. Beard, thanks again for the response. i am guessing that the pin on the "bulkhead" you are talking about is the fuse link? (what is a bulkhead?) i replaced it with an inline 30 amp fuse link. i still have no lights on the left half of the instrument panel, gas gauge, and the amp meter. by the way the amp meter seems to be more stable after i took the cheapie alarm system out. i found rust on the plug (on the left side) to the instrument panel and cleaned it, but it made no difference. so i guess i need to find out why it's not getting any power. thanks.

Bulkhead connector is another way of saying "the big black block with an array of a bunch of terminals that penetrates the firewall and has three other big black plugs in the engine bay that connect to it to provide all of the wires forward of the firewall a way to get inside the interior without having to pull them through grommets."

Your wiring is divided into segments, or harnesses. For instance, one runs to the headlights and running lights in the fenders and grill. The end of that harness has a bundle of wires terminating in a big plug. That plug goes to the bulkhead connector, so the lights can be operated by the dash switch.

Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

so... when i had the panel out, i checked the pins and connectors and i didn't see any that looked bad, so i cleaned them and put them back together. i really don't trust the amp meter, it flickers too much (the altenator has new brushes). the thing that i don't get is that when i first bought the car the gauges would be very dim, but they WOULD come on and now nothing. if it were a fuse they would have just went out. thats why i question the light switch. thanks.

Thanks '74 Sport - I've been out of town.

There is a fuse for the instrument lights; it is with the other fuses and usually says "inst" or something like that and you can see if it's blown with a test light. What does happen sometimes is that the dimmer (part of the headlight switch) goes bad; often, if you turn the dimmer up and down it may work intermittantly, especially if you push it side-to-side. See if you've power at the fuse with a test light, then try the back of the PC board.

After some years oxide can build up between the fuse and holder and stop working, but look OK. It is a good idea to take the fuses out and clean the contacts and the fuses every 20 years or so to prevent that.

K. Beard, thanks for the information. i will be working on the car tomorrow and i will check this out. i have looked at the fuses, but i need to pull them out to check if an end might be broken loose and to clean the contacts like you suggested. i left a question under "engine" asking about what to do for my "idle" problem and explaining what i'm going to try to do tomorrow. if you have any suggestions about my "idle" i can really use some help. otherwise, off to the shop it goes. thanks, again.

i just went out and put a 12v bulb across all fuses and nothing. i tested the bulb and it lights up at a 12v source. when i bought this car 3 months ago it had the fuse box and enclosed circuit board dangling. it looks to be still hooked up and the radio, blower, ect. works. i sure hope some genius didn't by pass it! what is the circuit board for? it mounts on the left underside of the instrument panel. i can't seem to locate it on the schematic. thanks.

Hmmm- no power at any fuse? If things work, either you've not making a good ground with the test light or your fusebox has been bypassed in some horrible kludge. Double check - with the ignition on, every fuse should have power.
If your fusebox has really, really been bypassed your best bet is to pull the whole underdash harness out - and that easiest done by removing the whole dash (not just the instrument cluster). I can only imagine that being done in response to massive damage to the harness and it should be very, very unlikely. I've seen a lot of damage over the years, but never somebody bypassing the factory fusebox entirely.
The big PC board on the back of the instrument cluster is basically it. There was an optional LED warning light for gauges (it should be visible on the gauge face, but is pretty small) that required a little extra circuitry, but it should be up with the gauge. The factory didn't leave a PC board hanging. They did leave little things sometime hang, but not a PC board. Could it be some leftover from an alarm system or fancy horn setup? A gutted garage door opener? A headlight delay?
I would look for where connections to that board go and for any clues on the board. If the factory put it in, it should have some Chrysler markings. Any chips or components should have some writing on them.
You've got your work cut out for you if your harness has been really chopped up. Most likely, it hasn't been- probably, it was just butchered a little here and there. You're going to have to play detectiive. One friend found some old TV parts spliced in under the dash in a rather mangy attempt to filter RF noise, so you may be suprised.
1974 models did come with an oddball starter interlock gizmo, but should be over by the glove box and have lots of wires comming out ot it. Usually, they were unplugged. It became legal to bypass the seatbelt - starter interlock in 1975, I thiink.

I forgot to suggest that if you're sure the fusebox has no power, take all the fuses out of it and see what works.

K beard: wiring is definitely not my strong point. the test light i used was probably the wrong one. i used to use it to set my points on my motorcycle a long time ago. i have another test light that has batteries. you ground the wire and touch the point to your source. i had already decided to pull the fuses out one at a time and see what goes out before i read your last post. i have the original shop manual. my question now is: is my 1974 scamp a (r-w), (p-d), or (c-y)? oh, i think that curcuit board is probably part of that cheapie alarm system i took out. good, i can get rid of some more dead weight. thanks.