Need a little help with my gauges

[79 USA 1]

Looking at the wire diagram from my 86 El Camino, Are you still running the computer control on this vehicle or have you disabled the system? Looking at the wiring diagram check the 10 amp fuse marked ECM IGN its up one row and to the right. Is the 20 amp fuse in the gauge position good? With the ignition on you should show power on at least one side, as well as at the power taps marked IGN above the fuse. If no power on either side did you pull the steering column down to disturb the wiring on the ignition switch?

 

[oldsmobile joe]

Looking at the wire diagram from my 86 El Camino, Are you still running the computer control on this vehicle or have you disabled the system? Looking at the wiring diagram check the 10 amp fuse marked ECM IGN its up one row and to the right. Is the 20 amp fuse in the gauge position good? With the ignition on you should show power on at least one side, as well as at the power taps marked IGN above the fuse. If no power on either side did you pull the steering column down to disturb the wiring on the ignition switch?

good point
you say you have no power at gauge fuse, next step is to check power at ignition sw.
check out the malibu racing site on wiring, https://maliburacing.com/wiring.html
click on " ignition switch " and review the wiring diagram.
power starts at the starter and travels through a fusible link to a splice s201 that branches off to the alternator and a/c, then travels through the firewall/bulk head connector c100. it then spits at s202 and creates redundant power wires to the ignition switch. the pink wire from the ignition switch powers the gauge and turn signal/buck up light fuses, it also powers the hei distributor.
check for power at these locations, all spices and connectors are to be considered suspect.

working backwards from the gauge fuse,

do your turn signals and back up lamps work, if so, ignition switch is good, you have a fuse block problem.

if not does the car start and run, if so, ignition switch is good. you have a wiring problem between c100 and gauge fuse.

if not, check for power at alternator.
if ok at alternator, check wiring to firewall connector c100. and check connector at c100

if you have no power to alternator, check wiring to starter, you may have a bad fusible link.

 

[bazthespazz]

The thing runs and drives. Turn signals work, not sure about the backup lights because I very sekdom drive it at night. I'll have to check that out.

 

[79 USA 1]

The thing runs and drives. Turn signals work, not sure about the backup lights because I very sekdom drive it at night. I'll have to check that out.

Do you have a simple test light? Something like this?

I'm not bring an idiot with this question but you need to check some circuits. Using the test light back probe the fuse for the gauges with the key in the run position, If you get a light on one side but not the other you have a blown fuse. Also check the IGN cavities, to see if you have power. Honestly it sounds like the 20 amp fuse on the gauges has a detached leg.

 

[bazthespazz]

I've got am OHM/VOLT meter and I just got done pulling it all apart again and no voltage at the fuse, either side. In the process of putting it all back together I broke the needle on my speedometer. Anybody know where I can get a replacement? Is it possible to run a new wire from one of the IGN connections to the pink/black wire that runs the gauges?

 

[grandamman]

Looks like just one ground and I'm guessing it's good since all the lights and the clock are still working.

Do the dash lights work?

"All the light work" so I'm guessing g that all the lights work

 

[bazthespazz]

"All the light work" so I'm guessing g that all the lights work

Correct!

 

[79 USA 1]

Question: when you do your voltage checks at the fuse and the IGN ports in the fuse box you do have the key in the run position with the battery connected correct?
The turn signals you said also work correct?
I'm looking between both wire diagrams for a 79 and a 86 and both show you would have no turn signals or back up lights if you were not getting power from the ignition switch.
Understand electrical issues are a SOB in person, Doing them from a keyboard is harder yet hence the redundant questions.

 

[bazthespazz]

Yes, checked voltage at the gauge fuse with the key in the run position. I haven't checked the IGN connection. I didn't think about bypassing the gauge fuse and using an inline fuse holder to feed the pink and black wire that feeds the gauges from one of the IGN connectors but that's my next thing to try.

 

[79 USA 1]

Ok looking at the wire diagrams below, first is from the 86 book second is from the 79 manual. The #3 circuit in both is the main switched power lead originating at the ignition switch at the top of the steering column (Red Arrows). It supplies power through the 20 amp fuse to the back up lights/ turn (#75 circuit) signals as well as through a 20 amp fuse to the gauges (#39 pink/black tracer circuit). If your turn signals and reverse lights work you are getting power to the #3 circuit as it feeds off that. At the fuse block you need to check for 12 volts in the 3 IGN marked taps above and below the 20 amp gauge fuse. if you have 12 volts there then it is a break in the wire between the fuse block and the pin #16 (Circuit #39 pink/black tracer). If no 12 volts it is an issue with the fuse or the holder it slips into. If you have no back up lights or working turn signals then you have to check for 12 volts at that fuse. The problem could exist from the ignition switch (Top of steering column Circuit #3).