LS 5.3 Drive By Wire ~ Stand Alone Wiring Harness (TAC Module) Question

**EagleMark** · 09-09-2013

I didn't mean post it all... just as you help in a thread, attach the info. Then it will never be lost, like if you linked it to where hosted at a website and things there change? Poof! We all loose info again...

Like this thread is a specific problem and we can always look back on it from a search.

**dave w** · 09-10-2013

I'm thinking it might be a good plan to leave the brake wire and stop lamp input wires in the harness, should I need to connect them later. I'm thinking I could connect the brake wire to ignition on, so a "brakes are off signal" is continuously sent to the PCM.

dave w

**Buzz** · 09-10-2013

The PCM is "smarter" than that ... a constant lack of voltage on this circuit (similar to when the brakes are applied) will set DTC P0719 (Brake Switch Circuit Low Input) ... while constant voltage on this circuit (similar to when the brakes are not applied) will set DTC P0724 (Brake Switch Circuit High Input).

As you stated, it might be a reasonable course of action to leave these wires in the wiring harness (just tucked away where you can get at them if need be), until you complete the first one of these off-road vehicles. After that, you will know definitively what you need / don't need on future wiring harnesses for this customer.

Just some thoughts ....

**Playtoy_18** · 09-13-2013

I haven't done a dbw harness yet,but subscribing for the great info.

**dave w** · 09-15-2013

Found this information at lt1swap.com ( http://www.lt1swap.com/wiringharness.htm ). One relay to supply brake inputs to both TAC and PCM.

The wire from the brake switch will need to wired to both (spliced together) with the relay input (termainal 85) and TAC module brake switch input. I've decided to use Hella Relays #75601 relays and Hella connectors #75610. Hella relays are used by the factory. I'm thinking why risk using low cost relays that are not weather proof? Cheap is not good

...good is not cheap!

dave w