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Discussion Starter · #21 ·
Never mind.... I found one and everything seems to go where it should...
I have another TAC I'm going to try.

I made all the changes Harley recommended, but I still get the U0107 error and the engine runs for a few seconds and dies...
I went back and used my trusty test light to verify every thing was good A to B.

Thanks...
 

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Discussion Starter · #22 ·
This is what I now have:

A8 - Orn Batt (pcm C1 - 20&57)
A9 – Driver side coil
B4 - DBW (TAC signal)
B7 - Fuel Pump Relay
B9 – Pass. Side coil
B10 - MAF
B11 – NSS Trans (pin 10)
B12 – NSS Trans (pin 9)
C8 – NSS Trans (pin 11)
C10 - Injectors (6 & 8)
C12 - Stop lamp Sw (C101 (D))
D10 - Injectors (2 & 4)
D11 - PPL Starter Solenoid
E2 – NSS Trans (pin 12)
E7 - Ground to engine (ground wire run directly to engine block)
E10 - Injectors (5 & 7)
F7 - PCM Ground
F9 - H02 Sensors (both)
F10 - Injectors (1 & 3)
F11 – NSS Trans (pin 1)

+ Trans power (E) to C101(G) (spliced with PCM C1-75)

repeating…
checked continuity on all wires involved
tried different TAC module (no affect)
added ground wire to: Tac module, PCM, TB housing

Results are the same…. U0107 “Lost Communication with Throttle Actuator (TAC) Module”

As usual, no clue to what to try next-
 

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Make sure that E7 and F7 are both grounded to the engine block. Also the PCM grounds need to go to to the engine block too.

E7 - This needs to be spliced with the engine grounds and grounded to the engine block


F7 - Ground to Engine block
I don't know if that will fix your communication issue, but if you send me a reminder message I'll look into the TAC wiring later today.
 

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Discussion Starter · #24 ·
Grounds:
Battery to engine block
Battery “pigtail” to frame, with a ground strap on to the radiator support
Ground strap from the firewall ground “post” to engine
Grounds from UBEC (E7), TB base, PCM cover, to engine block
Ground spliced into PCM ground going to UBEC C2-F7, and run to engine block

Part of my problem is that I wrapped most of the harness in the cloth “tesa” type tape, to protect it from heat. So, now it’s a B*%ch to locate things. That’s my excuse anyway…

So, the problem still exists, but I appreciate the efforts on your part.



Thanks…
 

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Discussion Starter · #25 ·
Sorry, 'nuther dumb question:

How do you determine a "Hot on Crank and Run" vs. a "Hot on Run" or "Hot on Crank" circuit?

Thanks...
 

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It's pretty self explanitory.
Hot on crank only has power, when the motor is starting, normally used for the starter circuit.
Hot on run, is most of the accessories and doesn't have power when cranking over.
Hot on crank and run has power when ever the key is on, if its on crank or run. Your injectors and ignition are on this circuit.
 

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Discussion Starter · #27 ·
On the 16 pin TAC connector there are four pins (4,5,6,14) that are Cruise Control related.
I'm not running CC, at this point, so can I just ignore these?

Thanks...
 

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Why no cruise? It's already built in.
 

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Discussion Starter · #29 ·
Don't have the cruise control switch (on the turn signal stem).

More interested in just getting the damn thing to stay running (U0107 code), so I'm looking for wires that need to be hooked up.
 

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Of the 4 it might need the CHMSL supply voltage - basically this is a brake switch input. Connector C1 pin 6.
 

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Don't have the cruise control switch (on the turn signal stem).

More interested in just getting the damn thing to stay running (U0107 code), so I'm looking for wires that need to be hooked up.
Well....that would be a good reason not to hook it up... 😂
 

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Discussion Starter · #34 ·
Can someone just tell me where this CC TAC(6) wire needs to go? The truck did not have CC originally, so there is nothing to start with, and I'm not going to hook it up right now.

Thanks...
 

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Fuse Block Connector C1 will have the CHMSL output on pin F11. From the factory Chevy split this between the Cruise Control Module and the third brake light. I passed this over to the Engine Harness using the C101 connector.

That's what I would do. It's a different circuit than the PCM - C1 (33), so I don't suggest combining the two functions.
 

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Discussion Starter · #36 ·
OK, on the C101 connector, did you connect it into pin (P) ?
If not, then I need more info. (sorry)...

Thanks for your patience with the wiring-challenged.
 

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Choose an empty pin. From the factory this won't be in the C101 connector.

Your truck doesn't have a connector for the Cruise Control Module under hood, correct?
 

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Discussion Starter · #38 ·
If the cruise control module is separate from the TAC, then No, all I have is the TAC, it's pedal to TAC and TB to TAC connections. I have the four CC wires, but none are connected at this time, and the truck did not have CC, so there is nothing to connect them to.

Thanks...
 

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I'm asking about your S10. Often times, even without the cruise option, there is the connector underhood. GM often used the same harness regardless of options.

It would be to the right of the brake booster. This would also have the light blue 1320 circuit wire and could be an easier source to connect to your TAC module.
 

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Discussion Starter · #40 ·
If you mean this guy (pic 1), It is the one from the Silverado donor. I mounted this on the firewall, behind the Intake manifold. The 4 CC wires come out of the 16 pin connector and are presently going to nothing. I don't have a turn signal stalk with the CC controls on it, if I add CC later I'll get one then.
The other pic shows the area I think you referred to where the unit is mounted from the factory (if it came with one).

Thanks...
Motor vehicle Light Electrical wiring Gas Auto part
Motor vehicle Hood Automotive tire Automotive lighting Automotive design
 
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