Mochi

Hey all, long time no see. I’m glad this forum is still active.

I’m lost, I’m having a hell of a time locating a on/acc trigger. My radio fuse on my 71 cutlass as well as the accessory fuse or post are completely unreliable. Sometime they function, other times not. Sometime they are constantly hot, other times the work as expected. I’ve been tearing my hair out trying to figure out the issue.

Is there an actual wire from the ignition switch to the fuse panel? What could cause this kind of behavior? Thoughts?

Thanks in advance.
P.s. I’ve removed or moved all new accessories to a new fuse block. So, it’s as stock as can be. I’m pretty sure all my grounds are good but will check again just to be sure.

Olds64

What accessories did you move to a new fuse block? Do you mean that the radio fuse in your OE fuse block is intermittently temperature hot, or just intermittently supplies 12V? Either way, this can be due to an intermittent short. Are your battery terminals and all of the accessory wiring you've done terminated properly with crimps, soldering and shrink wrap?

Mochi

Hi, thanks for responding. I moved: power windows, power locks, stereo and alarm to the new fuse box. I’m re checking the rest of my grounds today.

the radio is intermittently supplying a constant 12V.
Personally, I despise wire crimps, they are never as strong as I like. So, I physically twist my connections together and cap them.

Fun71

I hope you mean you’re soldering the twisted wires then using shrink tubing, and not twisting and taping.

Vintage Chief

Your issue speaks to one of two most likely scenarios: one circuit is most likely overloaded; &/or, at least one circuit is incorrectly wired. The resolution will require a detailed examination of the wiring using a multi-meter. Be certain you're using the correctly sized wires for each device within a circuit - measure resistance, amperage & voltage of each wire. Hook up one device at a time, measure the aforementioned parameters, turn each device on one at a time, measure same parameters in both the ON & OFF states. Add additional device wires to the circuit and again measure same parameters - write down each parameter so you can keep track of resistance, amperage & voltage. Evaluate the cumulative draw (amperage) - are you overloading a circuit? Compare the OEM wiring circuitry with your upgraded circuitry (new fuse panel). Ensure you are not using fuses which exceed amperage for a given circuit. I doubt it's a ground issue, you haven't stated anything is faulty - you said sometimes things work other times they don't. That speaks to incorrect wiring for at least one circuit.

The radio does not supply voltage. The battery supplies voltage to the radio and any other device. The radio, along with any other device consumes power (amperage) along each wire contained w/in the circuit.

Yes. 1971 Original GM Oldsmobile CSM Wiring Diagram A Body "V-8"

Olds64

Like Fun71 said, you can twist wires together and solder them. Wrapping connections with tape instead of using heat shrink is asking for trouble. You can buy it pretty cheaply at Horrible Freight. Wire nuts commonly used in household AC wiring (i.e. a ceiling fan or light switch) should never be used in DC, multi-strand wiring.

Make sure you're using at least 12 AWG wire for your additional circuits. Of course, a higher current draw from your stereo might require bigger gauge wire. FWIW, I used 10 AWG wire and the manufacturer's supplied 20 A fuses when I installed my ham radio in my 96 98.

Mochi

So update! When I changed my alternator, I did a single wire conversion. In doing so, I did not replace the ground capacitor on the wire. I reinstalled the ground capacitor and all is right.

for future reference to anyone doing something similar.

Mochi

hi!
All of my new accessories are on the new painless wiring harness. Only things running on the original harness is what is original to the car. :-)

oldcutlass

I don't see how a capacitor was causing your power issues. They are noise filters, without them you may get abnormal/unwanted radio interference but that's about it.

Mochi

🤷🏾 Beats the hell out of me. As soon as I put that wire back to ground all things returned to normal. Could it have been that capacitor wire serves a dual purpose as a ground?

Olds64

x2

If re-attaching the ground wire on your alternator fixed the problem you probably had an open circuit. I mention properly terminating, crimping and soldering connections because they are important to preventing electrical problems like intermittent opens and grounds. Twisting wires and covering them with tape is the same way the OE harness was done in my 86 Ford F250. Thankfully, all it caused was a few melted down switches that I was able to repair. In the worst case, improper wring can cause the whole vehicle to burn to the ground.

BTW, 100 and worst or screaming chicken? I'm just a dirty leg.

Mochi

yeah I was trying to track down the open Circuit, had the whole car part. After checking re-checking quadruple checking all of my new connections and my grounds. I re-inspected the alternator change. As soon as I added that ground back to where it would’ve been in the external voltage regulator all things return to normal.

thanks for the advice on the wiring. I will likely go back and solder.

82nd. I won’t hold your low energy grounded status against you ;-) lol.

cjsdad

If you use tongue-and-groove crimpers such as pictured below, the crimp style connectors are completely reliable. The flat style crimper that simply squish the connectors flat are terrible and should only be used for temporary connections. The crimper below are made by Ideal but Thomas&Betts, Klein, and even Harbor Freight offers a similar tool. The HF ones need to be hand picked because they have terrible quality control.

Olds64

To get good crimps make sure you use a ratcheting crimper with the proper jaw for the terminal you're crimping. Here's one.


You can also get them at HF, Summit and Jegs.

cjsdad

Racheting crimpers are great when using standardized connectors and wiring but they limit the amount of constriction on the wire. When working on automotive applications you will rarely find a connector that is specifically designed for the wire you are putting it on. The difference between American made and Chinese made connectors can be the difference between a good solid, tight connection and one that the wire pulls right out of. Not just the thickness of the metal in the connector but also the thickness of the insulation I probably have as many, if not more, pairs of crimpers than Joe Padovano has and for automotive wiring I prefer non-limiting crimpers. Packard crimpers and Packard connectors, Molex crimpers and Molex connectors work well together but a chinese ring terminal on the alternator charging lead might need a little extra pinch to make it tight and secure.