I have installed a 12V power outlet under the passenger's side dash to run my cell phone charger or my GPS. I connected it to the "Ignition-Hot" optional connector on the Under-the-dash-fusebox. I have protected this outlet with a 10A in-line fuse.

I may want to increase the fuse size from 10A to 15~20A so that I can also run a vacuum cleaner or air compressor.

I assume that the three optional connectors on the box [Ignition-on, Lights-on, Constant] are themselves fused but have been unable to find either on this site, the Helms manual or the owners manual what the fuse ratings are. XViper, in one thread, said only "that it's large". The Helms manual does say that underdash fuse #23 protects the "Option Connector" and a bunch of other stuff but that doesn't seem like that's the right one.

Does anyone know what they are actually fused for? Does each have it's own fuse or are they all protected by one fuse?

 

Good find on the fuse #23. To find out, pull that fuse and then check for power at the "IG-HOT" power tap to confirm. You may have found something that we can use in future.
If it still gives power with ignition on, then I'm guessing that the power tap is fused from one of the larger fuses in the fuse box near the battery.
For running things like vaccums and tire compressors, I would still splice on alligator clips and run those directly off the battery.

Of course, the one for "lights" will be fused off the same fuses that run the instrument panels illumination. The HOT-constant, I would also be guessing on this one, too.

 

Well I pulled fuse #23. I does NOT protect the "Ignition-HOT" Connector.

I would have really been surprised if it had been the one. It's only a 10A fuse and has a lot of stuff hanging off it.

Someday when I've really, really got nothing better to do I'll start pulling fuses until I find out which one does protect it. Guess that would be preferable to loading it up until one blows.

I had previously put alligator clips on the air compressor and vacuum...... guess they'll stay there for a while longer.

 

This may be a better indication that it's fused to one of the big fuses under the hood. You might start to pull fuses there while you have a multimeter hooked up to the power tap.

 

for an old thread.

Has anyone found out if those underdash power sources ( Ignition, Constant, Lights) have some kind of protection (fuse) anywhere?

In my case, I have four things tapped into the ignition power source.
1. relay (low side) for water pump for aftercooler
2. AEM serial gauge (for illumination)
3. Defi gauge (for illumination)
4. Defi brain (for illumination)

Will these 4 overload the ignition power source??

 

anybody?

 

no one has any insight?

 

see this thread

 

no, you should be fine

 

thanks