computer/wiring help needed

[tobysoldblue]

If i do away with the somg junk,will it throw my service engine light on?Also,my temp guage barely moves when the truck is warm,im guessing when the engine was replaced,a sender for a light was put in maybe?Is there a way i can test this theory other than buying a new sender?Id rather trouble shoot than throw parts at a problem.Also,if i do away with the factory sender/gauge,for an aftermarket guage,will the check engine light come on?Now for the most important question,as soon as hit i hit the switch for the left fuel tank,the truck dies.I put 5 gallons of gas in the tank to see if it was out,fuel guge still shows empty,truck still shuts off.Everything seems to work fine on the passenger side tank.How can i trouble shoot this too?Thanks folks

[Captkaos]

We need more information on what year truck and what came on it?

[VileZambonie]

Yes more info is needed. I posted the diagnostic circuit check for the fuel tanks in another thread.
The sending unit is not for the ECM it is for the gauge only.

[Click Here]

[and here]

[tobysoldblue]

Cool!I got both fuel tanks fixed yesturday,found another cut wire underneath.I also put in a new brake light switch,now at least the brake lights work,but still no cruise control.I drove the truck almost 200 miles yesturday,now the trans is not wanting to change one it gets warm.The truck is an 87 4 door dually,with a fuel injected 454,and turbo 400 tranny,4.11 gears.I hope i can change the fluid/filter for the transmissin,and it will be ok.The tranny was supposedly rebuilt about 30 thousand miles ago,when the engine was put in,but there is oil coming out of the valve  cover  oil filler cap too.Not a good sign to me.Im gonna change all the fluids and filters on the whole truck,tune it up(sparkplugs,wires,etc)and see what happens for now.

[VileZambonie]

Make sure you didn't cross the wires when you did your brake light switch with the detent switch for the trans. If there is 12v to the detent solenoid it won't upshift. Unplug the wire on the side of the trans and see if it shifts.

[tobysoldblue]

It shifts,when cool,it has a pretty loud whine(front pump goin out?)but once warm,like after driving 50-100 miles,it dont want to shift from second to third.

[comp]

lurking for info