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dash lights

3K views 9 replies 6 participants last post by  Rob Keller 
#1 ·
Hi all, need a little help with my dash lights not working. Car is a 68 impala. Please bear with me as my electrical skills are not great. But my first checks were the obvious. Replacing lights bulbs in the dash, no luck. So I check fuses and they all look fine, no luck there either. So I took a volt meter to the fuse box to see if I'm even getting power and all the circuits seems to be getting juice with the exception of the "instr lmps" fuse. So I think I'm onto something here. Problem is, I'm not sure what to do next. I guess I'll try to get behind the fuse box to see if anything looks out of place but I'm open to your expert opinions. It's amazing how dark it gets when it's nightime and you're crusing down a dark road, top down, and no dash lights :) Thx for the help!
 
#2 ·
Dash Lights

The power to the dash light fuse should be coming from the headlight switch. Turn the knob on the switch to see if the lights go on or blink. I don't have a wiring diagram for that vehicle so I can't tell you what color wire feeds the dash light fuse. But I would want that info, then back probe the correct wire coming out of the headlight switch itself. Odds are it's a bad switch, but it's always better to test first.
 
#3 ·
SIS you literally check the fuses with the test lamp?

Try looking for a bad ground .

Doc Vette :pimp: should be by here soon & possibly provide you with a schematic

Next would be the headlamp switch sometimes the get hot & melt the plug & the wires a common problem .

Sometimes the cigarette lighter is wired in with the dash & dome lights.







R :thumbup:
 
#4 ·
Could be a bad contact in the headlight switch.
Or--the ground on the rheostat(sp?).

As stated earlier---power runs from the switch--to the fuse--to the lamps--and back to the HL rheostat (lamp dimmer---dome light on)

You will only have power to the the inst. lamps, with the headlights "ON".

So--with headlights ON (or in park lamp pos.), check BOTH sides of the fuse.

Does the dome lamp work with the headlamp switch??? This might be a clue, but I doubt it. (the HL switch in my car has a cam that grounds for the dome lights)

Do the dash lights flicker at all when the HL knob is rotated???

Check these out

May be as simple as a new HL switch.

Oh---make sure you have a solid attatchment of the HL switch to the dash.
Could very well be the dash lamps are grounded here. IF the HL switch is loose there will be no ground.

Bryan
 
#5 ·
Doc here, :pimp:


Remove the FUSE...

measure with a METER, voltage at each foot..

you WILL have power at one foot of the fuse..IF so, jump the fuse holder , turn the lamps on, you should have lamps..IF not,

(no voltage, you have an open buss bar in the back at the fuse buss, try another fuse of equal amps for test jumping , if it works you need to repair or replace the buss bar or buss.)

GO to the switch, be sure the rheostat is not all the way down, with the lamps "ON" measure the voltage IN and OUT of the rheostat (big round thing at the end of the switch hooked to the linkage of the on/ON switch.) IF it is IN but not OUT the rheostat is bad..if it is not IN or OUT the switch needs replacement.

IF power is good out of the rheostat, then you have a cut or burned wire on the ISTR DIM line..hand over hand inspect it.


Doc :pimp:
 
#7 ·
ernkazern said:
Ignore what I said, I was giving you advice based on a wiring diagram for an 80 Caprice because my diagrams don't go back to 68. On an 80 caprice they vary the voltage to the dash lights through the dimmer switch. I guess it's the opposite for your vehicle.

Doc here, :pimp:

Back then, in the Olde Days...when Firestone was Flintstone tires.. :D

The basic logic flow was, power to the fuse foot 24/7/365..power out of the other fuse foot to the HL switch "Dim" terminal, then power OUT of the HL switch from the Normally open contact of the"Dim" terminal, then to a Big round Rheostat (wire wound resistor) mounted either at the front or back of the HL switch, with the linkage "bar " through it (to give the twist action) , and the other wire of the rheostat to the dimmer lamps..

Got that off my papyrus schematic..in my cave files.. had to translate the hieroglyphics...:D :rolleyes:


Doc :pimp:
 
#8 ·
I am new to the forum and you guys have already helped me out. My dash lights, as well as some other electrical issues, are corrected. After reading this discussion, I traced wires from the headlight switch, and so on, and so on, and discovered where bubba had previously been. Seven cut wires about 2 inches from their connector. They were twisted together and taped. Great feeling fixing stuff yourself. Thanks all!!! :D
 
#9 ·
66Chevy2 said:
I am new to the forum and you guys have already helped me out. My dash lights, as well as some other electrical issues, are corrected. After reading this discussion, I traced wires from the headlight switch, and so on, and so on, and discovered where bubba had previously been. Seven cut wires about 2 inches from their connector. They were twisted together and taped. Great feeling fixing stuff yourself. Thanks all!!! :D

Doc here, :pimp:

That's what were here for! :thumbup:

Good feeling Huh? :thumbup:

Have a Good..

Doc :pimp:
 
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