Dashboard accessories headed for a meltdown?



By Chris Dougherty
Chris Dougherty is a certified RV technician. Here is a letter he received from a reader while he was serving as RVtravel.com’s technical editor.

Dear Chris,
What is the best way to power all of the 12 volt accessories that I have? I do not want to overload the outlet on the dashboard of my Class A, but I do have a lot of “accessories”:

– Tire monitor
– Toad brake system monitor
– Radar detector (probably do not need this, not much speeding going on)
– Phone charger
– etc.

curiouslee on flickr.com

You get the picture. I have one splitter that goes from one outlet to two, but I do not want to keep adding more and more. Should I add more 12v outlets? If so, is that hard to do? Any suggestions are greatly appreciated. —Dennis

Dear Dennis,
Wow, you do have a lot of stuff on your dashboard! The good news is that most of the items you’ve mentioned are low amperage devices, and if you’re not blowing fuses, then you’re probably OK.

To determine this for sure, start with the circuit in the dashboard feeding the 12 VDC receptacles and see what that circuit is rated for. Your coach manual should be of help here. Next is to determine the amp draw of each item you are plugging in and add them up. Most devices will have their power requirements printed right on the device, but each item’s manual should be of help here as well.

The weak link may be the splitter. Most of the ones I have seen are fused in the plug to prevent overloading, but I would double-check and see if the amp rating is listed on it.

Again, the idea is to make sure that each item in the chain from the source to the load isn’t being overloaded,

If wiring clutter is a concern, or if you do happen to be overloading the circuit, or close to it, then adding 12 VDC receptacles may be a solution. Options for installing these vary widely, from tapping into an open space on the vehicle’s fuse panel and installing a new circuit that way, if the vehicle manufacturer has left a spot open for that purpose and approves it; or running a new, dedicated, protected circuit from the coach or chassis battery to the receptacles directly. In this case, it is essential that the proper circuit protection, wiring, connectors, receptacles, and wire protection (loom, grommets, etc.) are used.


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My truck is a 4×4 supercrew v-8 w/max.tow package,dealer said i was rated at 15000 GCWR. I did take your advice and talked to two different tire guy’s and both said that Michelin at/2 or the ms/2 work work for me.So thanks for the time and advise from you….


Russell Hutchison

I am not sure this is the right spot for this, …but here it is.. I am needing new tires for the truck ,f150 225/65/18 size…what do I need to pull a 35ft. 7600 lb. travel trailer. with about 900 lb. tongue weight. what I have will be ok, others say I need a heavier load tire. What is your thinking on this ….
Thanks Russ