The electronic throttle control light is flashing in my 2004 1500 5.7 Hemi truck, won't accelerate but does turn on, where should i start?

The lightning bolt on the dash means that there is a problem with the electronic throttle control system in your vehicle. Get a code reader and scan the engine for any logged codes. The light may be on for a glitch and the electronic throttle control system needs to be reset.

To reset the Dodge Ram throttle position sensor(TPS), You need to turn on the ignition without Your foot on the brake, so the engine doesn't start. Then press the accelerator on the floor for 15 seconds. Release the accelerator. Then turn the car off and start the engine and drive.

I think this means your electronic throttle control (ETC) has a problem. The ETC takes the signal from your accelerator pedal to control the throttle plate in the throttle body. See this link:

http://www.baraboomotors.com/what-are-those-warning-lights.htm

seems something wrong with the Electronic throttle control (ETC) which is an automobile technology that electronically "connects" the accelerator pedal to the throttle, replacing a mechanical linkage
There is no mechanical linkage between the accelerator pedal and the throttle valve with electronic throttle control. Instead, the position of the throttle valve (i.e., the amount of air in the engine) is fully controlled by the ETC software via the electric motor.
- you better have the ETC immediately serviced by an approved Toyota-shop
Electronic throttle control Electronic Throttle Control

The check engine light on?

You need the dealer on this one, sorry but since the part is sold as the entire throttle assembly and it is very expensive it must be properly diagnosed. Do not just throw a new throttle body on the engine as it may not fix the problem.

Take it to one of the bigger autoparts stores, they will usually scan for free, and determine what trouble code is actually present to verify problem area. The accelerator pedal position sensor is operated by a cable from pedal to APPS, then electronically from there to determine throttle plate positioning. The APPS is located under battery tray, but you can get to it over left front tire. Wait until trouble code is confirmed to determine repair.

I had the same problem with my, 03, hemi. I did not wait 15 min. turn off and back on was all that was needed to reset, "red flashing light lower right hand ". though another 8 or 9 on off's, Engin Light also goes off, untill next time. All i did was pulled off my Air Intake box and hose, so i could get to butterfly on throttle bodie, sprayed carb cleaner in there. and it was very dirty. after put back togather, give it a few.... mine did not start right up, when it did idle real ruff even died few times...Once the computer re adjusted ran like it did when i bought it....that was 2 weeks ago, still no eng light, no flashing red ones either.

the lightning indicator is for problems with electronic throttle.

Does it turn over? If not, try disconnecting the battery and reconnecting it. This has worked for my Jeep before.

I had same problem on mine. The wire harness under the throttle body cover rubbed and was cut in two. If you remove the cover and unplug the etc you can feed the harness under the plug wires to inspect them.very common problem on this vehicle.