RanchWelder
Full Access Member
- Joined
- Jan 14, 2023
- Posts
- 801
- Reaction score
- 1,146
- Location
- Earth
- First Name
- --------
- Truck Year
- 87
- Truck Model
- Blazer
- Engine Size
- 355ci
I'm rewiring a custom dash in my 1987 Blazer.
I'm used to just using my Amprobe with a pair of wire spikes and verifying these things as I need to.
Without power with so much of the dash opened and with thin gauge dash light kit in a custom aluminum entire dash console and dash board, I'm in the weeds.
* My battery is disconnected for safety because I have major wiring to do with fan relays, Compushift 2, 3 high voltage runs for the trailer brake controller Blue, a Red charging trailer wire and a 6 gauge hot run to my fuel tank yet to go.
The wiring diagrams are giving me a headache because they do not really specify the circuitry design or the correct wire color codes for the K5/K10, such as:
a) the single tank sending unit colors for sender vs power: (The wiring diagrams all show circuitry for the dual tank systems, as far as I can find).
I have purple, Gray and black. I'm reading 00.8 ohms between the Gray and Black ground.
32.6 between the purple and the black.
The fuel tank wiring question is required because I am attemting to over-size the main power wire.
I mistakenly stated months ago this upgrade was completed when I added the rear 175 A Buss bar, however when I dropped the tank to install new springs and the 14-B, the tank wiring portion of the project was not completed. Need to beef up that circuit.
b) the circuitry for the check engine light, ie: what color wire in the dash harness connector and does it get wired through the light to ground or does the ECM complete the circuit to ground to flash the light?
c) What color wire from the dash guages wiring connector is used for 4wd yellow light and how does it get a buzzer or a light?
d) Is there any provision for an alternator warning light or do I have to run a wire directly to the "I" terminal on my CS130 4 wire connector?
The connecter I have has only 2 wires in the connector and none where the diode circuit would need to be wired, according to a PowerMaster pdf I found.
e) My wires to the ignition column connecter are 16 gauge, not heavy duty 12 ga, like the pictures that instruct cutting the Purple wire for the ignition, on an automatic 1987, as the place to interrupt for Neutral safety.
This thread states in 87 the AUTOMATICS do not have a neutral switch.
This thread says the Purple wire is the correct place to cut for the Lokar neutral circuit:
Need to install Neutral Safety Switch on "87" to pass Canadian Inspection Auto to Super T-10 any suggestions on which wires would be appreciated :
http://forum.73-87chevytrucks.com/smforum/index.php?topic=39564.0
Can you confirm, please, this is correct and the Lokar switch can handle the full voltage this wire is sending?
I'm not certain if I need to add another relay in between or if this wire just sends a signal to the ECM to activate the starter relay circuit seperately.
Does it matter which side of the column connector I cut? I have a loop of wire that is purple under the connector, hanging down below the column that looks great, if it's correct.
f) where would you suggest I interupt the reverse light, so I can run it manually off a dash switch togle?
I see it's Lt Green and I know where the tail lights come through the firewall, however they turn into something else in the fuse box and get switched most likelt in the column.
Perhapse the same connector where the mysterious Purple ignition wire lives, might hide a back up wire color that will also allow me to cut at the column connector as well?
Again, I cannot test without making it hot and using my meter with spikes, so I'm in the dark.
The diagram is useless with regards to finding the way the circuits run off the page and do not connect to another page in the drawings, or maybe it's just me not finding where they run to another cut in the drawings.
When I cut the dash cluster connector off the dash harness, the Pink wire to the connector alternator circuit was factory wrapped, double back and cut 6 inches long, inside the black wrapper.
The other solid pink is supposed to be my fuel sending wire, so it's wired to my new auto meter fuel gauge.
Hopefully most of the diagram wire colors at the dash connector are correct.
I hope that my explaination is not too confusing.
_________________________________________________________
Here's the link to the post by "bd" where this .pdf file was found:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=39564.0
Using this diagram, found what I think is my 4wd circuit, IF my Blazer is the V300 version with just the 4wd indicator lamp and no shift lever circuit.
Could not define the V300?
Don't see where the Low 4wd buzzer used to live or how to wire it.
Hoping the brown with white stripe in the 4wd cut V300 is the brown /wt in the 15 pin on the cluster connector.
Have a yellow wire, which I think is the check engine in pin 13, but cannot be certain it is either hot or grounded by the ecm, as stated above.
I'm told the fuel tank sender will fry if I send the wrong wire 12v with a heavy duty power wire mod...
Suspect the yellow wire error might damage the ECM the same way?
No idea and not ready to burn up either unit.
I know where the fuel pump relay is and the wires do not match anything at the tank.
Anybody have experiance adding a heavy duty fuel pump 12v 10 gauge wire?
If so, what worked and how did you do it, and what should I be doing to occompish this task without 12v connected to test the circuit?
These six issues have cost me days or internet research, so I'm asking for your expert advice, please?
It's getting scortching hot im Montana and with thick cold weather blood, and a lot of stress from my 4L80E and transfer case re-manufacture, with a 14 bolt and spring swap, it's been tough.
We had snow 6 weeks ago and now it's 90.
I'm used to just using my Amprobe with a pair of wire spikes and verifying these things as I need to.
Without power with so much of the dash opened and with thin gauge dash light kit in a custom aluminum entire dash console and dash board, I'm in the weeds.
* My battery is disconnected for safety because I have major wiring to do with fan relays, Compushift 2, 3 high voltage runs for the trailer brake controller Blue, a Red charging trailer wire and a 6 gauge hot run to my fuel tank yet to go.
The wiring diagrams are giving me a headache because they do not really specify the circuitry design or the correct wire color codes for the K5/K10, such as:
a) the single tank sending unit colors for sender vs power: (The wiring diagrams all show circuitry for the dual tank systems, as far as I can find).
I have purple, Gray and black. I'm reading 00.8 ohms between the Gray and Black ground.
32.6 between the purple and the black.
The fuel tank wiring question is required because I am attemting to over-size the main power wire.
I mistakenly stated months ago this upgrade was completed when I added the rear 175 A Buss bar, however when I dropped the tank to install new springs and the 14-B, the tank wiring portion of the project was not completed. Need to beef up that circuit.
b) the circuitry for the check engine light, ie: what color wire in the dash harness connector and does it get wired through the light to ground or does the ECM complete the circuit to ground to flash the light?
c) What color wire from the dash guages wiring connector is used for 4wd yellow light and how does it get a buzzer or a light?
d) Is there any provision for an alternator warning light or do I have to run a wire directly to the "I" terminal on my CS130 4 wire connector?
The connecter I have has only 2 wires in the connector and none where the diode circuit would need to be wired, according to a PowerMaster pdf I found.
e) My wires to the ignition column connecter are 16 gauge, not heavy duty 12 ga, like the pictures that instruct cutting the Purple wire for the ignition, on an automatic 1987, as the place to interrupt for Neutral safety.
This thread states in 87 the AUTOMATICS do not have a neutral switch.
This thread says the Purple wire is the correct place to cut for the Lokar neutral circuit:
Need to install Neutral Safety Switch on "87" to pass Canadian Inspection Auto to Super T-10 any suggestions on which wires would be appreciated :
http://forum.73-87chevytrucks.com/smforum/index.php?topic=39564.0
Can you confirm, please, this is correct and the Lokar switch can handle the full voltage this wire is sending?
I'm not certain if I need to add another relay in between or if this wire just sends a signal to the ECM to activate the starter relay circuit seperately.
Does it matter which side of the column connector I cut? I have a loop of wire that is purple under the connector, hanging down below the column that looks great, if it's correct.
f) where would you suggest I interupt the reverse light, so I can run it manually off a dash switch togle?
I see it's Lt Green and I know where the tail lights come through the firewall, however they turn into something else in the fuse box and get switched most likelt in the column.
Perhapse the same connector where the mysterious Purple ignition wire lives, might hide a back up wire color that will also allow me to cut at the column connector as well?
Again, I cannot test without making it hot and using my meter with spikes, so I'm in the dark.
The diagram is useless with regards to finding the way the circuits run off the page and do not connect to another page in the drawings, or maybe it's just me not finding where they run to another cut in the drawings.
When I cut the dash cluster connector off the dash harness, the Pink wire to the connector alternator circuit was factory wrapped, double back and cut 6 inches long, inside the black wrapper.
The other solid pink is supposed to be my fuel sending wire, so it's wired to my new auto meter fuel gauge.
Hopefully most of the diagram wire colors at the dash connector are correct.
I hope that my explaination is not too confusing.
_________________________________________________________
Here's the link to the post by "bd" where this .pdf file was found:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=39564.0
Using this diagram, found what I think is my 4wd circuit, IF my Blazer is the V300 version with just the 4wd indicator lamp and no shift lever circuit.
Could not define the V300?
Don't see where the Low 4wd buzzer used to live or how to wire it.
Hoping the brown with white stripe in the 4wd cut V300 is the brown /wt in the 15 pin on the cluster connector.
Have a yellow wire, which I think is the check engine in pin 13, but cannot be certain it is either hot or grounded by the ecm, as stated above.
I'm told the fuel tank sender will fry if I send the wrong wire 12v with a heavy duty power wire mod...
Suspect the yellow wire error might damage the ECM the same way?
No idea and not ready to burn up either unit.
I know where the fuel pump relay is and the wires do not match anything at the tank.
Anybody have experiance adding a heavy duty fuel pump 12v 10 gauge wire?
If so, what worked and how did you do it, and what should I be doing to occompish this task without 12v connected to test the circuit?
These six issues have cost me days or internet research, so I'm asking for your expert advice, please?
It's getting scortching hot im Montana and with thick cold weather blood, and a lot of stress from my 4L80E and transfer case re-manufacture, with a 14 bolt and spring swap, it's been tough.
We had snow 6 weeks ago and now it's 90.
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