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Old 07-14-2007, 12:57 PM   #1
MiniD
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1971 K5 4x4 4-spd wiring harness questions

I'm finally putting my blazer back together and am scratching my head at the wiring schematics. I have just purchased a new harness from M&H and have worked with them enough to know that if something's screwed up, it's entirely my fault.

I'm trying to figure out what the connectors go to. I have a double wire connector that seemingly goes to the reverse sensor on the transmission, but I cannot find this in any of the 1971 schematics. The only mention I've seen of it is in a 1968 schematic that I saw in the factory assembly instruction manual. It's a dark green and light green wire.

I also have what seems to be an oil pressure sensor wire that is set up to plug in not to far from the distributor. I also have an oil pressure guage that plugs into the port right next to the distributor, but there is no connector on it for the idiot light signal. The idiot sensor is between the 6 and 8 plugs. I'm wondering if this is the right location.

In addition, the water temp sensor is located between the 1 and 3 plugs. But all of the drawings I have looked at show it up by the goose neck on the manifold. Does anyone know the best way to route the wire down to the side location?

A minor thing I noticed is that I have a purple wire going to the blower motor for my AC system. All of the 1971 schematics show an orange wire. I have a 1968 schematic with the purple on it, though. All of this stuff looks original and leads me to believe I'm just missing something when it comes to pairing the right year schematic to my truck.
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Old 07-14-2007, 11:46 PM   #2
72 CustomCamper
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Re: 1971 K5 4x4 4-spd wiring harness questions

Going by the 72 wiring diagram I have. Thr 18 gauge lt green and 18 gauge dark green wires are for the back up light switch on the trans. The water temp sensor should be in the drivers side head using a 20 gauge dark green wire. And the blower motor wire is a 12 gauge purple wire...


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Old 07-15-2007, 04:49 PM   #3
LUV2XCLR8
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Re: 1971 K5 4x4 4-spd wiring harness questions

"I am a bomb technician. If you see me running try to keep up!"

Nice siggy 72, "The Sum of All Fears" Very good movie
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Old 07-15-2007, 07:24 PM   #4
MiniD
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Re: 1971 K5 4x4 4-spd wiring harness questions

I did find the correct schematic under the AC section of the repair manual and only see mention of the backup light switch under the C30 section of the schematics. I'll have to piece all of those together.

I'm wondering about the two relays in the upper right corner of the firewall (engine bay side). They seem to be some kind of emissions devices, but they aren't connected to anything. Can I get rid of these?
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Old 07-15-2007, 07:58 PM   #5
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Re: 1971 K5 4x4 4-spd wiring harness questions

"Can I get rid....." . Yep.
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