fuse panel voltage, wtf?

lsejlowe

lsejlowe

Active member
Joined
Jun 18, 2008
Messages
41
Location
Wichita, KS, USA
the left half of the fuse panel has ~12V, but the right side only has ~.17V.

As I was leaving the dragstrip last night my instrument lights didn't come on. Fuse appeared to be good (until I broke it trying to remove it) and the don't come on when I jump it with a short piece of wire. My radio also no longer works, but the turn signals do. I removed the two screws on the panel to pull it off and see what's behind it, but it seemed to be firmly affixed even without the screws.

Where should I start? Does it sound like it's in the fuse panel itself?
 
lsejlowe said:
the left half of the fuse panel has ~12V, but the right side only has ~.17V.

As I was leaving the dragstrip last night my instrument lights didn't come on. Fuse appeared to be good (until I broke it trying to remove it) and the don't come on when I jump it with a short piece of wire. My radio also no longer works, but the turn signals do. I removed the two screws on the panel to pull it off and see what's behind it, but it seemed to be firmly affixed even without the screws.

Where should I start? Does it sound like it's in the fuse panel itself?
Click to expand...

Jason, Sounds like the black fusable link coming off the horn relay. Should feed a red wire that goes thru the firewall plug and feeds that 1/2 of the fuse block. The other fusable link is orange. It might even just be loose/corroded.
 
hot damn, I hope it's that simple. pardon my ignorance, but is the horn relay on the driver's side fender?

You got this whole damn harness memorized?
 
lsejlowe said:
hot damn, I hope it's that simple. pardon my ignorance, but is the horn relay on the driver's side fender?

You got this whole damn harness memorized?
Click to expand...

Yes. (To the relay location)
And no, I just checked the downloads section. I suggest you save it to yours.
I just finished helping a member trace out 2 issues on a '68. VERY similar schematics. Let me know what you find.
 
348d5b58153676.jpg
Ignore the new red wire with the auto/reset C.B. on the right. That is the feed for Scott's headlight relays.
See the black and orange wires (fusable links) with a black rubber grommet like affair. Check the black one, which becomes a red wire.
 
OK, got the black and orange fusible links. No obvious signs of either of them having burned. What's the rubber grommet thing all about? Is it just to protect the splice?

I've got 12V at the each terminal on the horn relay. What's the best way to see if I have 12V past the fusible link?
 
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lsejlowe said:
OK, got the black and orange fusible links. No obvious signs of it having burned. What's the rubber grommet thing all about?

I've got 12V at the each terminal on the horn relay. What's the best way to see if I have 12V past the fusible link?
Click to expand...

Take one of those cheap Autozone 12v test lamps, the one with the sharp point, and probe the red wire just past the black link. Clip the test light ground to a known ground. Probe the relay terminal to confirm this. Push the probe into the insulation till you conatct the copper.
The black rubber things are the molded insulation where the fusable link is spliced to the regular conductor.:wink:
You should also be able to check for 12volts at the wiper bypass switch on the firewall,. It has 2 large red wires, and operates off of the wiper door bullshit.
 
probed the red wire past the fusible link and still have 12V... :suicide:

What's wierd is that I now have 12V to everything but the instrument lights. I'm pretty damn sure I had the key on the first time because I tried the blinkers and they worked, but the radio did not. Both of those require the key to be in the "on" position.

One other thing... I'm not sure if I just didn't notice this before or what, but my Clock/Lighter/Courtesy fuse is now blown. It could very well have been blown to begin with since none of those things have ever worked, but I'm pretty damn sure I had 12V on both sides of it before.

Well, I'm going to grab a shower and hit the sack. Got an autocross to make it to tomorrow...
 
lsejlowe said:
probed the red wire past the fusible link and still have 12V... :suicide:

What's wierd is that I now have 12V to everything but the instrument lights. I'm pretty damn sure I had the key on the first time because I tried the blinkers and they worked, but the radio did not. Both of those require the key to be in the "on" position.

One other thing... I'm not sure if I just didn't notice this before or what, but my Clock/Lighter/Courtesy fuse is now blown. It could very well have been blown to begin with since none of those things have ever worked, but I'm pretty damn sure I had 12V on both sides of it before.

Well, I'm going to grab a shower and hit the sack. Got an autocross to make it to tomorrow...
Click to expand...

Allrighty then. There is a dark green wire from the headlight switch to the fuse block that goes thru a fuse then turns gray and feeds the instrument lights. If the dark green has 12volts, it's the fuse. If it does not, it's the switch, or you have the headlight switch rheostat turned down/off.
As for the latter issue, it is a different issue. The common problem is the clock points weld closed and overload the circuit. Disconnect the clock feed wire, and replace that fuse. See how you stand.
Good luck tomarrow.
 
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