64 F-85 electrical ribbon harness- highlight questions

[therobski]

Guys getting closer to getting this car in the street. Is there a replacement for the electrical ribbon harness that runs down the drivers side floor that runs power and connects to the rear harness? Mine is okay but would really like to replace it. Also are some of you running relays on the headlights to improve the brightness or replacing the headlights-I actually have the original old T-3"s

[H2Ogbodies]

Part of the issue with the GM headlight wiring in these older cars is the design itself-the headlight switch (and everything for the interior for that matter) pulls power via a single 12 gauge wire-and it comes from the horn relay common +12v buss terminal. Keep in mind the original alternator is only rated at 37 or 42 amps at most AND that the current must travel back out from the switch to the headlights.

All this serves to induce enough voltage loss (around 1.5V) to create less than optimum headlights. A relay kit will definitely help but an upgrade to a CS internally wired alternator would be killer for all the electrical demands! This is all assuming you are still running a stock GM style wiring layout underhood.

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1.5V voltage drop equates to roughly 20% more light output btw!

[therobski]

Yes I have 130 AMP internal Alternator, hopefully that will enough to support the A/C and a 250 Watt Soundstream AMP, HEI, PowerMaster mini Starter etc.

[H2Ogbodies]

I don't think your output charge wire is nearly large enough to support your electrical demands with having a lot of voltage drop. Try this:



Start the car, at idle turn everything you can on-stereo at a pretty loud level-measure the voltage @ a fuse panel BAT terminal inside the car-if it isn't rock steady at 14+ you need to upgrade.

[therobski]

H2OGbooies, notice next to the alternator there's a Painless 7 circuit panel I used to wire all the new accessories to. Also I have a volt meter as part of the new gauge panel inside. I have not started the car yet but getting close. Also have a neat led volt meter on the positive battery terminal. So what your saying is when the car is running it should read a min 14 volts correct?

[68nate]

I have upgraded my headlights with relays and h4 lenses and bulbs - 68 firebird. Power from alternator to junction on radiator support - all power distributed from here. Waytek sells some really cool power relay modules made by cooper busman - part # 37702-1an0022 Nice little compact relay setup with 2 separate J case fuse circuits and weatherproof connections. Relay is rated for 70 amps. Worked awesome for doing my headlights and way brighter. I have one for high beam and one for low beam both mounted right beside each other on radiator support facing forward passenger side covered by ac filler panels

[H2Ogbodies]

H2OGbooies, notice next to the alternator there's a Painless 7 circuit panel I used to wire all the new accessories to. Also I have a volt meter as part of the new gauge panel inside. I have not started the car yet but getting close. Also have a neat led volt meter on the positive battery terminal. So what your saying is when the car is running it should read a min 14 volts correct?

Correct 14V or higher BUT with as many things turned on as possible:turn AC in Hi, turn headlights on, turn stereo up fairly loud so it hits pretty good, run the wipers, leave door open for the courtesy circuit to be on, run power windows if ya got em....do all of this and measure the actual voltage inside the car-I'll bet it's in the area of 11.5-12.2 or so.

Measuring at the battery or alternator post doesn't tel the story-you want to measure as far away from the common junction as possible so you get a sense of your voltage loss downstream. I did a CS charging upgrade as well as an 8ga upgrade and re-wired a few areas underhood on a loaded 1970 Monte-I picked up nearly 2 full volts inside the car afterwards! There lots of ways to do it but I've measured results before and after so I'm very familiar with what's needed to maintain high voltages on even a stock setup for the most part. The higher you can keep the operating voltage, the less amp draw that will be required.

[Mr Nick]

For a great headlight upgrade get these:

http://www.summitracing.com/parts/hla-002425811
http://www.summitracing.com/parts/hla-002850811

and this:

http://www.ceautoelectricsupply.com/...relaykits.html

I also use a 4ga fused cable off the alternator.

[therobski]

These are really good ideas thanks a bunch. I actually copied them to a word document and printed them! Now I still would like to know if there is that ribbon harness replacement available from someone....

[68nate]

My 67 Bonneville has the same Ribbon running under the carpet down the center hump- splits about at the rear of the front seat running out to both sides for rear doors for power windows - Just finished installing new carpet over it. I have never seen this available anywhere.

My thought on fixing it if something ever failed was to just run regular wire inside the flat conduit that you use to hide your wires to your wall mounted TV

I was a little concerned after installing the new carpet as I had to reshape it in a couple spots where it had popped out of its plastic sheath and was pushing on the plastic trim piece between the doors.

Made sure to verify everything was still working before installing the extremely awkward and heavy power bench front seat

No Issues after reshaping it in 2 spots -seems pretty beefy

[therobski]

68nate good ideas especially making sure everything works before you put the carpet and seats in!!!