19Tyler74

Hello all,

Was looking for some advice on where to start on my 74 with my loss of lighting inside the vette - all the gauge lights are out and it does not appear that any fuses are blown... the door lights come on however once a door is open...

Thanks!

7T1vette

Broken or disconnected grounding wire(s). There is one for the center gauge cluster that runs to metal framework around the cigarette lighter area; the speedo/tach ground wire runs from backside of speedo housing to the left side [front] door jamb frame.

Do you have lighting in the transmission tunnel area?

If you have no lighting inside the car (except for door/interior lights), see if the headlamp switch **** is rotated to the "low" or "off" position. The instument lights all work off that switch (for 12vdc power) and the rotation of that **** dims/brightens them. If you turn it full CW and still no lights, either the IP light fuse is bad or the dimmer part of the headlight switch is defective.

19Tyler74

Thanks a lot for the advice - I think it's a ground issue near the kick panel on the drivers side... I thought the door lights were out as well till I bumped a wire by accident which in turn triggered the door lights on... I guess I will have to investigate that further...

As for the headlight switch, it is pretty loose - maybe it's no good anymore... how difficult are they to replace? I struggled removing that panel when I was in the process of restoring the interior...

7T1vette

It's a PITA, but it can be done.

#1 Pull the battery cable off before you start!

You really need a copy of the Assembly Instruction Manual (AIM) for your year car. It has all the detail of how 'stuff' goes together [or comes apart].

Basically, drop steering column a bit (don't need to remove it); remove attachments for the upper dash pad; pull pad off the retaining clips and lift it as much as possible without overstressing it; reach in between upper pad and top of driver's dash pad to 'do the deed'. The AIM will make sense on all of that.

19Tyler74

Thanks a lot - hopefully it will be something minor instead perhaps associated with the door jamb wiring...

drwet

I have replaced the light switch in my '79 but I've never had the dash pad out. I can't remember the details, but you may need to remove the instrument cluster, which might be easier than removing the dash pad. I would also be concerned about damaging a 30 year old dash pad by trying to lift one side of it. Have a good look at it befor etaking it apart to see what makes the most sense to you.

haydengm1

You might want to disconnect the speedometer cable.
That really frees up the movement of the dash panel the headlight switch is mounted on.

Easy Mike

You have a different dash. Your light switch is a heckuva lot easier to get to than the 68-77 models.

0Willcox Corvette

This pic may help you with what is going on in the switch.. or how to test function.

Peterbuilt

Tail light fuse feeds the headlight rheostat.
Jumper from "Courtest Light Fuse" to "Instrument Light Fuse"
if dash bulbs light up the rheostst in the headlight switch is bad.

Center gauge cluster and wiper switch ground through center terminal of
water temp gauge (14 gauge black wire).
The other end of that ground wire attaches to the left birdcage just above the left dash.


Schematic if you need it...
http://www.nrjvette.com/johdotukset/...tte%201974.pdf

19Tyler74

Much appreciated - the diagrams and advice are very helpful - hopefully I will get to the bottom of it today... so nice out though, may end up driving it around instead!
Thanks so much!