No spark please help

[Sauer1]

Hello over the weekend I worked on my truck a 97 Dodge Ram 1500 5.9. I started getting a leak on the left side of the timing chain cover. So I pulled it all apart and replaced the gaskets put it all together tried to start it but the only thing it does is crank over. Found out im not getting any spark. The coil has to plugs in it. A coil wire going to the distribuator cap (sorry for any spelling errors) and a two wire plug that plugs into the coil. From the two wires I used a test light grounded to the battery. When key is turned on I get power to the test lite for about 3 seconds then light goes out. But when I start cranking engine over I get no power to the test light. My friend has a 92 dodge dakota when using the test light on his wires he also gets a light for about 3 seconds then light goes out. But when he cranks his truck over light does turn on. Exactly the opposite of what mine does. So my question is what could be causing problem. Computer or module. If anyone has a suggestion I would be happy to listen. Thank you

[Justan02Ram]

might be a crank sensor.

[BleedDodge]

That would be my guess. How odd.

[slantsixness]

My guess is:
You left something unplugged.
The crank sensor went bad, or the wiring to it.

The 3 second power at the coil is related to the throttle kicker circuit and is normal (any where form 2-5 seconds). Not having a light (or an ignition pulse) when cranking is NOT normal.
Check your computer codes. If the crank sensor has no output it will give you several codes, including the crank sensor code, since the motor won't run you can expect the O2 sensor code, low temp etc....

Slantsixness