Tapping a Switched 12V Source – Info for Those Still Searching (25 Gen 2 Tri Max)

[HaveBlue]

Where did you get such detailed car diagrams?

I'm currently having a problem with my R1T. The left side of the car is "dead" because both 12V batteries died, and replacing them with new ones didn't fix it. Both batteries start at the same time, but the left side of the car isn't receiving 12V power.

Sounds like a Gen 1. If the entire driver side is dead it's likely a fuse at the battery or it require a hard boot. Here are the fuse panel layouts though:
Passenger side

Driver Side

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[R1Thor]

Used one of these connectors and just shoved it in place. was a tight fit and made descent contact shoved against existing wire - tugged on it a bit and it didnt seem to move at all so im happy with it - also more comfortable than tapping an existing wire

I'll probably get blasted for being sensationalist, but I would be remiss not to forewarn everyone:
this is a bad idea.
I used to work in the connector industry (7.5 years, but who's counting) as a Development Engineer.

Those connectors aren't meant to have 'extra' things jammed in there.
And.
The terminals that are mounted into the housing are done so with compliant pins that 'snap fit' into the plastic housing.
Depending on how you press another thing in, you're potentially actually starting the 'disconnect' between the terminal and the housing.

Meaning over time, with normal vibration, not only is your 12V source going to disconnect itself, but the pin that's in the housing is going to come undone.
That's best case.
Worst case is it just 'starts' to come undone, and eventually you end up with arcing, which will inevitably lead to failure, the magnitude of which will vary based on how much current fails through there and what it's connected to on the other end.

Anyway, I'm sure I'll get 12 armchair quarterbacks telling me this is fine and nothing bad will ever happen, but for the one guy who's reading this and going "oh, that makes sense, maybe I should do it the *right way*, then that's what I'm here for, and you're welcome"

So, what can you use?
T-Taps, wire split taps, or you can find a depinning tool kit and remove it, snip the existing pin off, pull back the jacket, and then re-crimp into the pin your cable and the existing cable, add a dab of rosined solder for good measure, and snap fit it back into the connector housing.

Or you can cut the wire back further and do a similar splice with a solder heat shrink connector.

 

[gbonsai]

I'll probably get blasted for being sensationalist, but I would be remiss not to forewarn everyone:
this is a bad idea.
I used to work in the connector industry (7.5 years, but who's counting) as a Development Engineer.

Those connectors aren't meant to have 'extra' things jammed in there.
And.
The terminals that are mounted into the housing are done so with compliant pins that 'snap fit' into the plastic housing.
Depending on how you press another thing in, you're potentially actually starting the 'disconnect' between the terminal and the housing.

Meaning over time, with normal vibration, not only is your 12V source going to disconnect itself, but the pin that's in the housing is going to come undone.
That's best case.
Worst case is it just 'starts' to come undone, and eventually you end up with arcing, which will inevitably lead to failure, the magnitude of which will vary based on how much current fails through there and what it's connected to on the other end.

Anyway, I'm sure I'll get 12 armchair quarterbacks telling me this is fine and nothing bad will ever happen, but for the one guy who's reading this and going "oh, that makes sense, maybe I should do it the *right way*, then that's what I'm here for, and you're welcome"

So, what can you use?
T-Taps, wire split taps, or you can find a depinning tool kit and remove it, snip the existing pin off, pull back the jacket, and then re-crimp into the pin your cable and the existing cable, add a dab of rosined solder for good measure, and snap fit it back into the connector housing.

Or you can cut the wire back further and do a similar splice with a solder heat shrink connector.

Makes sense - can switch it to a posi-tap still ensuring this is my best wire to tap before going more of a permeant route. as it stands there is no movement in it at all - red plastic cover was slid up after words to further add pressure to the connection.

hoping i can find someone else who has tapped this and knows what it goes to - or tapped something better in the vicinity - not looking to run a wire from the engine bay - may run a wire from battery under passenger seat and use a relay off this.

 

[tahoer1s]

Sounds like a Gen 1. If the entire driver side is dead it's likely a fuse at the battery or it require a hard boot. Here are the fuse panel layouts though:
Passenger side

Driver Side

Thanks for sharing this!

Dumb question - It looks like there are a lot of spares. Are those active 12v connections that could be used with a fuse tap?

 

[HaveBlue]

Yes there is likely a ACC switched bus and Constant 12V bus in both panels.

 

[birming]

I have 2025 R1S Gen2.
I wanted to use the power from the rearview mirror to install the dashcam, and I didn't want to plug the pin wires directly into the connector, so I looked for connectors and was able to buy them from a company in China.
Luckily, I bought 5 as samples before the tariff war, assembled 1 set with a USB-C power connector, and it's been working fine for 3 months now.

 

[Oldsmobile_Mike]

So, what can you use?
T-Taps, wire split taps, or you can find a depinning tool kit and remove it, snip the existing pin off, pull back the jacket, and then re-crimp into the pin your cable and the existing cable, add a dab of rosined solder for good measure, and snap fit it back into the connector housing.

Or you can cut the wire back further and do a similar splice with a solder heat shrink connector.

Thoughts on Add-a-Fuse? These are always my preferred way of wiring in things like Dashcams on the fleet trucks I work on.

Idle curiosity, what are folks doing on the 2nd gen vehicles?

 

[gbonsai]

Thoughts on Add-a-Fuse? These are always my preferred way of wiring in things like Dashcams on the fleet trucks I work on.

View attachment 144318

Idle curiosity, what are folks doing on the 2nd gen vehicles?

View attachment 144319

Curious here too for gen2. believe a relay is going to be the best bet - with it tapped off a wire similar to what I have shown at start of the thread. no Issues here yet with tripping or disabling anything with the extra voltage draw that i have added. liking the wire that ive tapped so far, shuts off almost instantly with closing door and walking away - or within 5 minutes of leaving the door open.

 

[R1Thor]

Thoughts on Add-a-Fuse? These are always my preferred way of wiring in things like Dashcams on the fleet trucks I work on.

View attachment 144318

Idle curiosity, what are folks doing on the 2nd gen vehicles?

View attachment 144319

Definitely a good and safe option if done properly.

Fuse within ~12 inches of power source is preferred, but not required. Obviously if it's a fuse tap that's adding a theoretically 'extra' fuse spot, you're AT the source, so, that's great. Regardless, just make sure your fuse is sized at approximately 10% more than your peak current draw expectation (which should also be well under the rating of the cable and connectors carrying the current).

Example: if you're installing a dash cam that requires ~5A, the next standard size fuse is 10A. That's fine. 14 gauge copper wire is typically rated for 20A. Still good. If you want to be extra safe, there are 7.5A fuses, if you can find them. Don't go crazy and put a 20A fuse on a 14 gauge cable for a device that only draws 3A, as a counter example. Because then there's a chance the fuse won't even have the opportunity to do its job, depending on the type of short or over-draw scenario.

 

[HaveBlue]

Thoughts on Add-a-Fuse? These are always my preferred way of wiring in things like Dashcams on the fleet trucks I work on.

Idle curiosity, what are folks doing on the 2nd gen vehicles?

You'd need a maxicompact compatible tap.

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