I'm installing my aux fuse box right now and I need to find a fuse that is hot when the ignition is turned on (I'm using a relay). It has to be in the engine bay. I would check myself but I dont have a battery because I am in the middle of a 3.4 swap. I dont think the headlight or hazard lights are ign hot but what about the charging fuse?

 

Your doing a wiring harness merge and unable to figure out a ignition switched power source. Why would you need a battery??

How many amps does the new circuit need to draw?? That is the important question.

Are you looking for a switched power supply to energize a relay coil to supply direct battery power to the new fuse block??

Why does it need to be in the engine compartment??

I know just How I would do this but curious to see some other replies.

 

I'm using a relay. So yes it is going to power a relay. I feel like I said that. And I dont have an 88 ewd just TheMonch's body plug pinouts. Simple question. Does the charging fuse go hot on ignition? I dont want to route a power wire into the cab because it would be a pain in the ass. I already have the accessory wires in the engine bay.

 

Sorry then I am unable to help.

Good Luck

When I ran a extra fuse block I ran the power off the unused rear defroster circuit

As this will not work in your case Because it is inside the cab.

It worked for me but I thought others would have much easier ideas.

 

My EFI fuse used to run hot and would blowout and I would have to replace it every week.I checked my manual and tried retracing the where would the short be but it was so hard to tell.I did a TPS replacement because my timing was off and so far no blowout of fuses and I had to replace the EFI fuse socket with another fuse holder soldered in.