Big 3 cable upgrade crashes into ohm's law

[thegawd]

Hell Ya! I have a pic somewhere with one of my headlights modded and the other untouched, the difference is huge and I only use oem cheap bulbs because they last forever. I actually I have a whole thread on this on GMTC. but that site kinda drives me crazy with SPAM!

 

[PlayingWithTBI]

That being said the wiring for the headlights leaves a lot to be desired. A relay setup is a must IMHO.

It's the same with the A/C clutch on my 88. It didn't have a relay on the firewall, GM ran the wire straight from the I/P. It was only getting 11.4VDC. After hooking up a relay, I'm now getting 14.2VDC and the clutch doesn't slip anymore!

The wiring diagram also shows .8 wire size going to my low beams which are 55Watts each so, 110W/12VDC = 9.17 AMPS on a wire that's ~18GA, ridiculous!

 

[PlayingWithTBI]

BTW - here's a conversion chart.

https://www.lapptannehill.com/resources/technical-information/metric-to-awg-conversion-chart

 

[TheAutumnWind]

It's the same with the A/C clutch on my 88. It didn't have a relay on the firewall, GM ran the wire straight from the I/P. It was only getting 11.4VDC. After hooking up a relay, I'm now getting 14.2VDC and the clutch doesn't slip anymore!

The wiring diagram also shows .8 wire size going to my low beams which are 55Watts each so, 110W/12VDC = 9.17 AMPS on a wire that's ~18GA, ridiculous!

The headlamp wiring runs all the way to the switch in the dash and back out to the lights too. Thats why everyones switch burns up.

 

[PlayingWithTBI]

The headlamp wiring runs all the way to the switch in the dash and back out to the lights too. Thats why everyones switch burns up.

Yepper!

 

[Pinger]

That being said the wiring for the headlights leaves a lot to be desired. A relay setup is a must IMHO.

Hell Ya! I have a pic somewhere with one of my headlights modded and the other untouched, the difference is huge and I only use oem cheap bulbs because they last forever. I actually I have a whole thread on this on GMTC. but that site kinda drives me crazy with SPAM!

Where do you take the main feed for the relay from when you do this?

 

[sntrym]

Where do you take the main feed for the relay from when you do this?

Battery feeds the relays (one high, one low), relays accept switched incoming voltage from the oem harness, then out to the new harness. You can buy the entire kit to do this for ~$25 and it's worth every penny. I did mine last year finally.

 

[dave s]

With all that said, I'm still going to do a big 3 to my truck. To be honest we all probably spend money on things that others think are unnecessary all the time! Lol. I know my wife does!!

 

[BOOT]

As others mentioned corrosion

Also check out the cranking amps of the starter, even tho it's large it is undersized for the load but it's short term use.

I've upgraded wiring in older(even low mileage) vehicles and had good results.

Had a friend get a caddy real cheap, they couldn't figure out what was wrong with it. After going thru the normal list he found it was a bad negative cable, look newish but was corroded bad on the inside.

Part of my list of things to do with a new project car, clean and replace batt cables & grounds, they always run better after.

 

[PlayingWithTBI]

Where do you take the main feed for the relay from when you do this?

Battery feeds the relays (one high, one low), relays accept switched incoming voltage from the oem harness, then out to the new harness

Yeah, that's one of the reasons I did my little upgrade. I'm feeding the fuse/relay box with 4GA to the power strip then 12GA to each fuse then the relays so, they all have dedicated protection.

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