73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Electrical => Topic started by: vtvette on June 11, 2015, 01:04:56 pm
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Hi all, I'm finishing up a complete rewire on a neighbors 1985 C10 2wd pickup. The previous owner swapped in a 454 from a 1994 Chevy Suburban, tried to piggyback the suburban harness onto the stock 1985 harness (one of the worse wiring jobs I've ever seen and I've done a lot of wiring) apparently could not get the stock FI to operate so they bolted on a carb and sold the truck.
I removed all the wiring from the truck headlight to taillight and replaces it with a bone stock complete harness I found at the local salvage yard (SCORE!). Everything works as it should but I have a question regarding the alternator:
As this is a 1994 454 in this truck it has the stock CS130 alternator. I used the stock CS130 connector from the 1994 suburban harness and connected it to the wires on the 1985 harness.
from the four pin/two wire black connector at the CS130 alternator one wire is connected to +12v the other (brown wire) is connected to the original 1985 alternator brown wire. This wire, circuit #25 on the GM wiring diagram, shows it leads to the firewall bulkhead connector then to the cluster where there is a Generator/Alternator light. My question:
I don't see a Generator/Alternator light in the stock cluster. I believe this is the original 1985 cluster. It has a large speedo and fuel gauge (no tach). If the cluster does not have an idiot light for the Gen/Alt (can anyone confirm?) then I need to add one to the tan wire circuit #25 to provide the proper resistance correct?
I just want to be sure I have the alternator wired correctly.
Thanks for any help,
B
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All I can confirm is that they either had the gauge package or indicator lights. The wiring harness and engine sending units are also unique to which package it has.
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If the 85 "has" factory gauges: circuit 25 connects to ignition through a brown, single-strand resistance wire, which substitutes for the charge light.
If the 85 "does not have" factory gauges: circuit 25 connects to ignition through a charge light in the cluster and a brown multi-strand wire.
See SI to CS Alternator Conversion (http://novaresource.org/alternator.htm) for more detail.
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If the 85 "has" factory gauges: circuit 25 connects to ignition through a brown, single-strand resistance wire, which substitutes for the charge light.
If the 85 "does not have" factory gauges: circuit 25 connects to ignition through a charge light in the cluster and a brown multi-strand wire.
See SI to CS Alternator Conversion (http://novaresource.org/alternator.htm) for more detail.
For a SI to CS conversion all you need is a pigtail from Napa.. EC80 has no resistor and EC82 has a reistor. Its a plug and play harness for SI to CS and how I put a CS144 into my 74.
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Thanks everyone for the help this is crystal clear to me now.
My final question - I assume this truck has what is referred to as the "Gauge Cluster" (has factory gauges)? as it has a large fuel gauge on the right, speedo on the left, and fuel/oil pressure/volt meter gauges. (does not have a factory tach in the cluster).
I can't find any pic's of what is referred to as the "idiot light cluster" (or non-gauges cluster)? I assume that is a bare bones cluster that uses lights as opposed to gauges?
Thanks again!
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Thanks everyone for the help this is crystal clear to me now.
My final question - I assume this truck has what is referred to as the "Gauge Cluster" (has factory gauges)? as it has a large fuel gauge on the right, speedo on the left, and fuel/oil pressure/volt meter gauges. (does not have a factory tach in the cluster).
I can't find any pic's of what is referred to as the "idiot light cluster" (or non-gauges cluster)? I assume that is a bare bones cluster that uses lights as opposed to gauges?
Thanks again!
You are correct in that assumption. I will try and post a picture this weekend just to clarify. I've not caught overheating problems in the past until it was too late. I personally prefer the lights, they get your attention. I will install a good set of mechanical gauges I would then refer to. Sometimes the factory set is very inaccurate.