74 challenger - dash wiring/switch testing

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Old 08-19-2012, 02:30 PM
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Exclamation 74 challenger - dash wiring/switch testing

i went blind starring at wiring diagrams, and just when I finaly decided it was a switch, we went out and grabbed a set of switches off his parts car. and what do ya know, they still wont work!

I spent alot of time with a multi meter and test light, and jumping things here n there, checking voltage drops and continuity etc etc..

everything seems fine, however it just wont work.

so what Im looking for is how to test the switches themselves, IE, which prong should connect to which prong etc.

these old wiring diagrams arent quite letting me in on something. Im running in circles totaly missing something, I just cant nail it down..

I've found one or 2 threads here in regards to the wiring/dash lights and they've helped me to understand a few things, but argh.. just not pinpointing it..

Colored wiring diagram I found in google pictures:

http://www.classicindustries.com/ima...m/ml13062b.jpg

if anyone knows what prongs of the headlamp switch connects to which prong when turned on, and same for the dash light dimmer, IE which is power in, and out, and to where, that would be great.

(Note: I belive the big wire going into the top of the switch is ONLY for the headlights correct? and it sends power OUT on the green wire?) which tests and works properly..

I've disconnected things and split the circuit in half etc etc.

essentialy, if I jump a power source from the headlamp input to the tan output on the dimmer control, the lights will work. now if I use just one/either of the switches, and use a jumper for the the other, they wont work. I have 2 sets of switches, but it seems like non of them work.

also, if anyone happens to know which fuse under neath is for which circuit, that would be a very valuable piece of info.

If I understand correct, power goes through the headlamp switch, back to the fuse pannel, through a fuse then to the dimmer switch, then to the lights correct?

anytips/guidanace would be great.

Sad part is, I have access to Shopkey5, and although im not too fond of it, (i perfer alldata to be honest) it doesnt have any info for the 74 challenger, and doesnt go back any farther. Out of curiosity, I know how old cars/manufacturers can be, was wondering if theres any other models/years (74 & up) that I could look at that would be the same.. ??

thanks for your time and patience.

(At first I just happend by while he was working on it, and kinda got into it a bit, thinkin it would be easy, simple, as im sure it still is. then we had a beer and mulled it over and studdied wiring diagrams. then we tested and dug deeper. then he offered me 50$ if i could fix it. (I told him a beer or two while we tinkered would be more than enough. How could I not take an oppurtunity to get inside such a nice car!!) Now I just want to figure it out cuz its DRIVING ME NUTS!!! and I'll never be able to raise my head again due to wounded pride.. :banghead:

~L~
Old 08-19-2012, 04:22 PM
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electrical problems are tough ive had my share i feel for u
im just going to make suggestions here since i don't no all the ins and outs of ur tests
from my experiences
check the grounds all the grounds trace the grounds to their sockets clean contacts fresh wire old wire can cause allot of trouble
use a continuity test and a amps test on all circuits / wires
if it comes down to it u can rebuild the circuits my brother and i have done this over the years and vehicles and had no problems
good luck hope it works out for you
Old 08-19-2012, 07:14 PM
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I have to tell you you REALLY need to get a REAL Chrysler corp factory shop manual, either find an original, a paper reprint or one on CD Most other wiring diagrams I've seen leave something to be desired, and manage to leave out a lot of stuff

Sometimes in order to figure out a switch (wipers, especially variable speed are the toughest) you must look at the diagram and figure out what all the wires going to it DO

Fortunately with Mopars, they used the same color coding for years and years, so this can help

Most Mopar headlight switches work the same except that yours has the instrument dimmer mounted separately

The headlight switch RECEIVES TWO separate sources of power:

#12 BLACK is ONLY headlight power going to the switch. This is supplied UNFUSED from the battery infeed through the bulkhead, which (in general) branches off and supplies the fuse panel "hot" buss and the feed to the ignition switch. Once again this is UN fused

#18 PINK is tail/ park/ instrument lamp power going TO the switch from the tail fuse

One TRICK on the instrument lamps is that the instrument dimmer control receives power FROM the headlight switch in park or head, so the control is also receiving power from the tail fuse BUT

The output of the instrument dimmer feeds BACK to the fuse panel and SUPPLIES (output of the dimmer) to the special, separate instrument fuse on #18 TAN. The output of that fuse branches off (ORANGE) to feed off to all instrument dimmer controlled lamps

Other wires also connect to the output of the tail/ park contacts, no18 BLACK goes down to the kick panel and to the rear for the tail lamps, and no 18 BLACK/ YELLOW tracer runs up through the bulkhead to the park and marker lamps

Headlight switched power comes OUT of the switch on no 18 LIGHT GREEN and feeds TO the dimmer switch, where it splits to high or low beams, and goes out through the bulkhead to the headlights.
Old 08-22-2012, 07:04 PM
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The Best

The Company called RS Restoration he is one of the ventors on this site he is the BEST person to ask knows ever thing about MOPAR wiring send him a e-mail mailto:jsrestorations@rocketmail.com He rebills all switchs and rewires dash tell him Greg told you
Old 08-26-2012, 02:43 PM
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hey all, thanks for the replies.
After the post, I took a break and went for a rip on the dirt bike, got back home, had a beer and reproccessed everything in my head.

I went back to a more methodical approach to it all. I was trying to do so much at once before, that I started overlooking some of the basics, loosing track of what was what n what I had learned.

Essentialy, I found one of the dimmer switches to be good.

I then took one of the headlamp switchs, got it apart, cleaned it up n tweaked it, and managed to get it back together and in working order. Doesnt look too pretty now, but you wont see that part anyhow behind the dash.

I then reviewed the wiring diagram etc. In the end, it was narrowd down to the PINK wire not having power. I think if a recall correctly, it may be grounded/shorted out.

I'm just waiting for my ride to come, then we'll be heading to my shop, to get my multi-meter, 2-way test light, and power probe.

If I recall correctly, the pink wire may be the one that is "welded\solderd"

I'll do a couple quick checks, but Im pretty sure I'll just be runnin a new wire of the solenoid were the rest of the cars power is provided from, and with a 20A inline fuse, run that up to the pink wire at the lightswitch plug.

I'll be snipping the terminal and length of wire off of his parts car, so I can just remove the original pink wire from the plug, and install the cut pink wire terminal from the parts car into the plug. (I just cant bring myself to hack into the factory wiring. I'll repair it to original wiring in the future when time and weather permits.)

I found that when jumping to the pink wire, I had power to the tails and dash lights.

anyways, thats how she went for me!

hope this helps any future issues ppl may have!

~L~
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