99 chevy silverado won't start in park **** will

Probably the transmission internal mode switch . But , without hooking up a scan tool an checking for DTC'S - diagnostic trouble codes an checking input data from the switch to the TCM - transmission control module i'd only be guessing . You don't want to waste money just replacing part's . Have a qualified repair shop check it out. Need factory service info an professional type scan tool .

Circuit/System Description
The transmission manual shift shaft switch assembly, also known as the Internal Mode Switch (IMS), is a sliding contact switch attached to the manual shift shaft inside the transmission case. The Park/Neutral Position (PNP) Switch is integrated into the IMS and connects to the Transmission Control Module (TCM) lead-frame through a short wire harness. The 5 inputs to the TCM from the transmission manual shift shaft switch assembly indicate the transmission gear selector lever position. This information is used for engine start enable, engine controls as well as determining the transmission shift patterns. The state of each input is available for display on the scan tool. The five input parameters represented are Signal A, Signal B, Signal C, Signal P (Parity), and Signal N (Park/Neutral Start Signal). Park/Neutral Signal is sent from the Park/Neutral switch directly to the Engine Control Module (ECM) and is used for engine start enable. The Park/Neutral Signal circuit is not connected to the TCM internally. The circuit uses the TCM as a pass-through connector only. The ECM Park/Neutral diagnostic monitors the Park/Neutral signal circuit to detect low voltage when the ECM expects high voltage and high voltage when the ECM expects low voltage.

DTC P1825: Internal Mode Switch - Invalid Range
DTC P182E: Internal Mode Switch - Invalid Range
DTC P1915: Internal Mode Switch Start/Wrong Range

Check the distributor

-Check "headLight fuse"
-Check connector at the headlight.
-Check the bulb. (It could burn out)

Mai

check high tention coil wire, coil wire going to dist cap with test light, if test light light up, it good also check dist rotor, and if that good might be pick up coil , the module might be bad, let me know what happen Bob

Is there any shift lock button near gear lever if yes than push it and give it a a try if no than I think you have you flush the gear oil and replace the gear filter too.

Same problem here, found break in wiring harness at cross-member behind cab. did have bed removed for easy access. Ground wire guilty party.

Your shift indicator is out of alignment or your shift linkage is out of adjustment. If you have the shift lever all the way up and are sure it has locked into park try shifting to Neutral and see if you can start it in neutral. If it starts this is a simple adjustment. if it doesn't you will need to replace the neutral safety switch or have the TCM repaired at a transmission shop.

neutral safety switch on the driver side of the trans where the shift cable hooks up.

Sounds like you have a defective neutral safety switch. The switch is normally found at base of steering column near floor pan.

pretty hard one.
First check th e bellhousing to make sure no wires got caught.
Check starter for broken wires.
Put emergency on and adjust linkage for the stops to be correctly aligned.go underneath and loosen the 1/2 bolt on the linkage make sure trans is in park and move until it can't go up any more.
.
That's
your starting point. now put gear shifter in neutral. feel the play in thetop
then in the bottom. you must equalize these distances so same loosness up / down..
If that doesn't work write back.