Installing Fused Switch in Dash

[John_M]

Next week I'll be helping a "mechanically challenged" friend install a lighted toggle switch in the center of his dash panel somewhere below the radio (he thinks). A 12ga wire from the switch will be run back to his factory installed trailer hitch. He and his 2003, 4X4, 47re/SO, SRW are out of town and I had only a few minutes this week to look at the dash and under the hood for connectors, etc. I have not yet seen the toggle switch but I would imagine it has a grounding connector on it. This toggle switch will be constantly "hot", much like a direct battery connection but I don't want to connect to the battery. There is a female brass threaded receptacle in the fuse box within the engine compartment and I could use this for power but then would have to find the threaded stud (probably metric) to use for the connection and would also have to install an "in-line" fuse holder.

There is a 12V receptacle in the lower left center of his dash below the radio almost at floor level. This receptacle appears to be unswitched, fused (20A?) and always hot so I would like to splice into it for power. I have all the necessary quality wiring, connectors, crimpers and solder to do the work properly but am unfamiliar with the Dodge setup. I am more concerned about doing the job right than doing it fast-but I don't want to spend all day on it. Here are my four questions:

1) What is the "trick" to removing that receptacle from the lower part of the dash panel?

2) Where is the best place to run one or two 12ga. wires through the firewall?

3) Is there a convenient common ground connection under the dash or should I just look for a metal chassis connection and self-thread a screw w/star washer through the sheet metal?

4) I should disconnect the battery to do this work because I'll be splicing into and working with a constantly "hot" wire. However, if I am very careful, I can probably do the work without causing a short circuit. If I do disconnect the battery must I reset codes or do some other work with which I am unfamiliar to get his electrical system working properly again? Should I leave the battery connected or disconnect-what do you recommend?



Some of you board members have already done a lot of this kind of work on your 2003 Dodge trucks. I feel much more comfortable using your experiences rather than "winging it" on my own and discovering later-on that there was a better way to do it.



Best Wishes,



John_M

 

[BarryG]

John:

I have an 01 so this may not apply.



Since he has an auto there should be an unused grommet in the firewall just to the left of the steering column where the clutch would have gone through that is plenty large enough.



There is also a chassis ground on the drivers side about bottom of the dash heigth next to the parking brake pedal. You might also be able to tap into the ground of the accessory outlet you are tapping into for the power, or the radio ground as well.



Can't answer the removal question never tried.

 

[wlowe]

If I am reading this correctly, you plan on wiring the switch in series with the main power. I guess this would work if the switch is rated at a high enough amperage to carry the potential load. I personally would come off the battery with a fused wire and use a relay to bypass the switch. This takes the load off the switch and the OEM wiring. If you do a search on relays there should be plenty of info. Your scenario is similar to a dash switched backup light installation so you might have some luck doing a search on "backup lights" also.



Good Luck

Bill

 

[Prairie Dog]

There is a large rubber plug on the drivers side firewall, (even if he has a std transmission) that can have a hole pierced in it (with an ice pick) and then your wires can be safely run through it. If you need more info I can post a pic. If your looking for a place to put the switch, there's a blank panel under the middle air outlet in the dash (std cab trucks have an air bag defeat switch there I think). Finally - don't worry about setting codes just by disconnecting the batts.

For anyone who wants to add backup lights, the standard wiring can support two 55w bulbs (it was built for this) in addition to the stock lamps, Just tap into the feed for the trailer connector.

Iv'e had mine hooked up for months now.

By the way, I agree with Bill. While most of the cheap light switches claim they can handle X amps, they soon fail so a relay is the safest bet.

Good luck,



Scotty

 

[John_M]

Thanks for the tips, Barry, Bill and Scotty. Friend returned to town a couple of days ago. He will have a local hitch installer with a very good reputation install the lighted dash switch along with an elecric brake controller. Just as well, I guess. I'm getting too darned old to be crawling around under trucks anymore (65 this July).



John. Oo.