You can buy one. Less than $5. I hope you are referring to the cigarette lighter 12V plug. They do make ones that you plug in on one end and two output on the other ends. That will probably save you a bit of elbow grease. I belive you can get them at Walmart or the Source.
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Be careful whose advice you buy, but be patient with those who supply it.

if you want an "in-dash" unit get it @ Pep boys or whatever local auto parts store you have, Simply get to the back side of the existing outlet and test to see which is the + and the - using a test light. Then use butt connectors NOT VAMPIRE TAPS! to get a spare pos and neg by bringing a spare wire out of each. The ends of these wires go to the new outlet, positive to center and negative to the outer shell.
Follow instructions on package for hole size to drill in the dash or drill slowly using a vari bit and keep checking the fit as you go.
Hope this helps!
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R Jackson
Owner/Installer
TRM Emergency Vehicles
Information is advice only and should be confirmed with OEM or quality test equipment.
Boyertown, Pennsylvania