Hi. Please don't let Blazer die so far away from home So I have a 96 Blazer 4.3 4wd, 4 door auto trans. Few days ago I replaced starter and during replacement noticed small leak from the fuel tank. Next day I went to my friend to fix hole in tank and close to his garage PRDNL indicator became strange - it displayed only P an D (RN and Od in dark) whereas gears seems to swithcing OK. I left car in garage where tahk has been taken off, fixed and placed back. Wen I drive to home, PRNDL indication became totaly crazy - It displays only D, sometimes it blinking. When I shift lever in different positions "D" light in Od, D and 2 position. Onlce I had 1 lighting for short time. Ok, this is "good" news. The "bad" one is that next morning I can't start - starter cranks the engine but no firing. I checked all the fuses, fuel pump works. Even disassembled instrumental pannel and check all the lighting diods under the PRNDL - they are ok. So I assume some electrical problem and suspect it is connected to the strange behavior of PRNDL. I need your help....

Thanks.

 

This issue with the gear indicator has been been brought up a few times, but I cannot find a thread in which a solution was reported.The best I can determine is that it is an instument cluster failure.
As to the non-start situation, you need to determine if you have spark to the plugs and test to verify the fuel pressure readings.

 

As far as I can see after instrument cluster disassembly, there is almost nothing to be died - only simply chip and few resistors. But, of course it is possible. My assumption was is that some switch exist somewhere on gear shifting lever which tells to "engine brain" which gear now engaged. And that switch has bad connection. As both (indication blinking and non-staring engine) occured close in time, that could be the reason - the brain recieves invalid data from gear switch and prevent engine to start. Only problem is that I failed to found that switch to check As for fuel pressure - it is ok, I have checked that.

 

Does the 'security' light on the instrument panel flash on and off when you try to start the engine? If so, the ignition switch (not the key cylinder) may have gone bad.

 

Never saw "security" lamp at all. Thanks, will check if it (may be just need to replace bulb). But note, starter engages. If it is security, then assume should not be any reaction on key at all, isn't it?

 

If the ignition switch is failing there may, or may not, be a reaction from the starter.

 

When the ignition switch on my 97 failed, the security light did not illuminate. The starter turned the engine, but there was no spark. As riddle suggested, check for spark. Start by pulling the coil wire from the coil, insert a metal conductor into the coil tower so that it touches the coil's metal contact and check to see if spark jumps from the conductor to the metal clip in the coil wire boot when the starter is turning. Beware that if you have been trying to start the car a lot, the plugs may be fouled with gasoline. That may prevent the car from starting once you restore spark, until you remove the wet plugs and dry them out, or replace them.

There is a neutral safety switch that prevents starting in any gear but Park or neutral. I would suspect if that failed, the starter would not energize. When I see lights acting as you have described, I look for a bad ground connection.

 

The security light deal is only on the 98+ trucks.

 

PRNDL switch is located on shift shaft at driver's side of transmission. Remove nut from shaft, then lever, then two bolts from adjustment bracket to tranny case. Check the electrical connector first & try some contact cleaner. Mine had some male terminals pushed back in connector & female terminals spread badly enough to make contact problematic (ham-fisted plug-up @ transmission o'haul?). Your back-up lights & starter interrupt are in this switch as well & it's pricey enough to warrant melting the plastic pins which hold it together for a clean-up & some fresh silicone grease on the contacts. There's a formed rubber gasket between the switch halves to create a seal & #4 screws & nuts will do the job of the removed pins after some cautious drilling.