My 2008 dodge ram cames to a sudden stop when in reverse.

Check the bulbs. DAYTIME Running Lights are controlled by the Body Control Module. You need an auto electrician for that.

No fuse covering them.

https://fuse-box.info/dodge/dodge-ram-1500-2500-2002-2008-fuses

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Check Fuse 7. Scroll down to 2008 fuses box.

https://fuse-box.info/dodge/dodge-ram-1500-2500-2002-2008-fuses

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Do you have access to a test light ?

Try ebay for the door as replacement for the 2008. It will list what it will fit. Sort of a reverse interchange chart.

I would start with the throd body and Mass Air Flow system for build up, do not listen to anyone who tells you that low grade gasoline is ok for you to use, your engine will not perform well on it and will cause a sticky residue on the throd body and MAF sensor. Also it is critical that you keep your truck with a clean air filter and service with oil changes and spark plugs as needed, follow dodge reccomendations, I learned the hard way 1994 Dodge Ram PU 1500 Quad and 2008 Dodge Ram 2500 PU both were the same way, they both had trouble with AC and Radiators as well.

hope this helps

Stop by any good parts store (Autozone, Advance, etc...) and have an OBII scan done (fault scan) They do this FREE - this will identify what's troubling your truck. It sounds like a vac leak or crank sensor but that's speculation... Have scan done then you'll know what to look for and you won't be throwing parts at it.

check the power distribution box, located under the hood on the drivers side for fuses and relays.

There is a pressure sensor in each wheel one of them is bad it's pretty common

Costly,porbably needs a transmission,like most chrysler products.

have you checked the air filter? could have picked up some trash and clogged the air intake.