Replicating factory TP2 option on an '02 GMT800

[mordimort]

Hello,

I've been working on replicating the factory wiring for RPO code TP2 (dual batteries separated by an isolator) on my 2002 Chevrolet Suburban 1500 LT and believe I have all the information necessary to do the under-the-hood wiring, but several forum posts mention that the OEM auxiliary battery relay trigger wire connects to the isolator/relay -> connector C100 in the underhood fuse block (UBEC) -> through the firewall to the driver footwell fuse block (MBEC). However, none of the posts I can find mention what connector is being connected to in the MBEC. Does anyone know this information? Additionally, would anyone know exactly where C100 is in the underhood fuse block (UBEC)?

Thank you,
Mordi

Under the hood wiring references:

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

I do carry a second battery in the second battery tray, but it is not hooked up with an isolator. I have high amperage quick disconnectors, and I can plug in the second battery, if ever needed. Of course, I have to periodically connect the second battery to the system to maintain its full charge.

 

[Doubeleive]

Hello,

I've been working on replicating the factory wiring for RPO code TP2 (dual batteries separated by an isolator) on my 2002 Chevrolet Suburban 1500 LT and believe I have all the information necessary to do the under-the-hood wiring, but several forum posts mention that the OEM auxiliary battery relay trigger wire connects to the isolator/relay -> connector C100 in the underhood fuse block (UBEC) -> through the firewall to the driver footwell fuse block (MBEC). However, none of the posts I can find mention what connector is being connected to in the MBEC. Does anyone know this information? Additionally, would anyone know exactly where C100 is in the underhood fuse block (UBEC)?

Thank you,
Mordi

Under the hood wiring references:
View attachment 462188

View attachment 462189
View attachment 462190

I suspect you will have to locate and reference a factory service manual to make it "factory" otherwise you can just install a battery isolater, run the necessary cables and go about your day, there are tons of isolators on amazon of all types. manual, electronic, remote control you name it.

 

[mordimort]

After researching countless forums and manuals, it appears the wiring for the factory TP2 isolator relay trigger circuit is as follows:

GM 12135194 relay -> GM 12052641 two-pin connector (aka Aptiv/Delphi Metri-Pack 150 2 Way Female Connector) -> UBEC C100 pin N (aka Ignition 3 Voltage) -> MBEC SEO pin E (also referred to as pin 4 in some diagrams, only hot in run/start, 10A fuse). The second pin for the relay/connector is a generic ground to complete the circuit.

In order to retain the factory relay behavior but avoid running additional wires from the UBEC through the firewall to the MBEC and having any visible fuse taps in the UBEC, I have decided to tap C100 pin N to the wire connecting to C1 pin A9 (circled in pink in the below image) in the UBEC fuse junction block with a 10A in-line fuse between them. C1 pin A9 provides voltage to part of the fuse block only in run/start, and tapping it with a 10A in-line fuse between it and C100 pin N perfectly replicates TP2 behavior with the same level of fuse protection as the factory connection to MBEC SEO pin E.

I have documented the required parts list in order to perform this modification as well and will post it here for future reference:

Many of the cables are discontinued, but at least at time of writing are still easily found on eBay and similar. They would be easy to DIY as well if you have some eyelet terminals and crimpers.

Thanks everyone!