12-volt tap

[tanker]

Where is a good source to get 12-volts only when the ignition key is on. We are looking on my sons 04 2500HD, but it seems like the only way is a brass piece that fits over a mini fuse. Well the fuse will not go in all the way with this little tap. Hate to use a scotch connector. There must be some place that a good connection can be made. ;)

[White Truck]

Tom,
Are you needing this underhood, or inside cab? There are usually unused terminals available in the Relay block. This block is the one the trailer brake harness gets plugged into. The plug to the right of the brake connector is used for select ride, so will be unused in the Dmax. There is on terminal that is a switched 12v source. I hate the fuse taps, as they damage the teminals the fuse plugs into and can cause problems later. They have to be left in once installed, or the fuse will no longer make good contact.

[mdadgar]

You are wise to stay away from the little spade plugs that go into the fusebox. I have personally witnessed a fusebox require replacement due to use of those.

I needed a switched 12volt source with decent current capacity (18A) for the compressor for my air suspension. I took the truck to a local stereo shop and they wired in a slick setup with a power block under the dash with dedicated runs from the battery and ground using nice, heavy-gauge wire. It's controlled by a relay that's tapped into switched 12volt, so it's only hot when the ignition is on, and is fully fused.

Cost about $100 and well worth it. The installation is very clean. Stereo shops do this kind of thing for a living - give 'em a try.

- Mark

[ 12-16-2004, 06:09 AM: Message edited by: StrangeEngine ]

[Lawnboy]

White Truck,

The relay block just to the right of where I plugged in my trailer brake harness has an empty socket. One of those IS in fact 12V switched. However, is there a specific crimp on spade type connection that will slip over this type of terminal? Big ones are too big, small ones seem too small and fragile. The instructions call for this to be a FUSED and switched 12V source. So I would then need to add an in-line fuse for this.

Plus, the snowplow manufacturer only supplies mini fuse taps that as tanker stated fit the fuse just fine, but won't insert back into the fuse holder all the way. This method would be fused by the fuse that I'm tapping. This feed is NOT for any high amp applications. It's used just to trigger relays.

I just wish GM would offer more assistance/directions with its products. I have the VYU Snowplow prep, but all it seems to give me is the little beacon switch on the dash. There is NO firewall hole anymore (you have to drill your own) and I'll be darned if I can find any type of "extra" headlight harness plugs up front.

Thanks for the help guys!

[Spindrift]

Lawnboy,

Try these guys. They make a neat secondary fuse block that you can run off the main block. It will provide multiple connections for both switched and non-switched power.

Painless Wiring (http://www.painlesswiring.com/)

[Turbine Doc]

Tanker,

Many auto stores carry the Painless taps; the one I have allows for use of orginal fuse plus allows addition for second fused circuit with separate pigtail to wire new circuit to, instrument illumination should not pose that big a load/concern, you can put the tap with one of the larger fused circuits, I have had my 3 gauges lights tapped to the instrument cluster fuse so I get dimming also no problems there in 2 years.

If you need hi current capable source, go with a relay fused from main aux terminal block, and use the switched fuse tap to control the relay that will keep load safe the relay coil won't draw much current, main load will be carried through the relay to the aux terminal. Relays also available from auto part stores.

Get with Jim to put us together email wise and I'll shoot you a photo of what I'm taking about.

[tanker]

Tanks for the help guys, ;) Lawnboy seems to have it under control at the moment. You would think that the manufactures would have a convient place, say under the hood, for some aux connections that would be fused, with both ign on, and constant on. As he stated the snow plow prep package is not enough, as a hole in the firewall for running the plow light and controls harness was used up by GM. :eek: So an angle drill and hole-saw at the clutch master cylinder location did the job. Oh well! :rolleyes:

[rjwest]

I f you are going to be adding more " Accy Switched "
circuits, it is better to install a relay.
I do not like to load the Ign Sw circuit...

Same for Trailer running lights, Relay driven by
Light sw circuit.

Installed a " Painless " fuse block, really cleaned up the Rats Nest I had created....

The Painless Fuse block comes with a " ACC " relay
for Accessory switched power and some non-switched power.