GM Genuine Parts 12135037 Multi-Function Diode

Works as intended. Bought this for the alternator I installed in the tractor.

I bought this GM multi-function diode to do the alternator voltage boost mod after upgrading my vehicle to a high-performance AGM battery. It tricks the system into bumping up the charging voltage safely to around 14.4V–14.8V, ensuring the AGM battery stays fully and properly charged. Installation was incredibly straightforward, though note that depending on your vehicle's fuse block layout, you might need to use a dual-fuse tap setup or slightly trim/shave down the plastic shoulder corners with a utility knife to clear the slot. Once in, it worked exactly as advertised. If you drop it in and get a dashboard battery light right away, just pull it out, flip it 180 degrees, and reinstall it. An absolute steal of a mod compared to expensive aftermarket voltage boosters! FYI, Arrow on diode points to the firewall on the 4th Gen 4Runner.

worked good.

Diode fits an inline fuse holder and together these provide a sturdy way to feed the alternator field coil the required starting current while preventing battery drain when ignition is off.

I have several older model vehicles. Both With AGM type batteries, however the original electrical system and alternator were designed for the original flooded lead cell acid battery design. This diode is a game changer in improving the performance of the charging system on these older vehicles. So that the AGM battery can fully charge. This diode fits with some very minor modifications . You have to trim away some of the plastic casing around the diode so that it will fit in to the fuse slot correctly . Performs well in my vehicles, 89 & 97 Toyota land Cruisers.