realestatesales

I have a 1997 with a 4.3, It's been running great with few problems and now has 105k miles. Yesterday it started fine but when I started driving it didn't want to shift out of first gear (4l60) when it did go to second it hit hard. I continued driving to see if it would shift but it wouldn't. I also notice that the speedometer stopped working and the engine was idling rough. Well I turned it off and it wouldn't start back up, it only cranks. There is no power to fuse # 20 Ignition, from reading the other forums it sounded like the ignition switch might have gone bad. I grabbed one from a junk yard since it was only 15 bucks but it still isn't firing. Do you know or have a wiring schematic? What could the cause be for no power be? Help please.

realestatesales

More info/// I had repaired the trans a while ago and found the lead that goes to the speedometer sensor on it had been pinched under the trans mount, I cut and respliced the wires to make sure they weren't cut but I thing this may have shorted out at one point. Could this have shorted out the ECM? How can I test it with a test light, volt meter or do I have to use a scanner? Thanks. Nick B.

MT-2500

Salvage yard is not a good place to get a good 97 switch.
Better go new one and see what it does.

On the transmission shifting the speed sensor/or circuit will have to be working.
A good transmission capable scanner will give your the read out on all sensors and or transmission problems and or codes.
If it has codes post back code no.

For a wiring diagram of ign switch and transmission wiring you need a good factory repair manual or the all data sub.
http://www.alldata.com/products/diy/index.html

__________________
Remember proper testing gives us the answer to many problems.
MT

ItsNotFyi

I have had SIMILAR issue... I have a 97 Blazer 4.3 The transmition is a (4L60E) I went ot leave work one day and it felt as if the truck was takin off in 2nd or 3rd gear... The next day... the truck was fine! 3 days later same problem once again! So I went through the pain stakin effort of replacing the 1-2 and 3-4 shift selonoids and new filter because everything I read said..."IGNITION SWITCH" and I was tooooo stuborn to see any relation what so ever! Needless to say it worked for about a day or two then went right back to same problem! On and off for days... About a week into this senerio my windows would'nt operate and as I proceeded to drive I noticed the shiftin problem once again but this time my abs light and airbag lights began to flash when ever my truck decided to have this transmission issue... I went in the store and once again!Everything was fine! So I decided to give in to this "Ignition Switch" issue... I took off the ignition switch cover thats located right under the key tumbler. With the windows not workin I held the window button down and turned key to the "ON" positionand tapped the ignition switch... well as odd as it is... my windows worked again... I drove away and holly crap! The druck drives fine too! The next time my windows stopped workin I proceeded to test the theory. I didnt tap the ignition switch... I just drove the truck to see what the transmition would do... wouldnt you know it... damn tranny acting up! I pulled over shut the truck off... held the window button down again and tapped the switch... and Wala! Window and truck work fine! I have not gotten to replace the ign switch yet but I am certain that even though it may not sound relative it has to do with the electrical outputs to different parts of the vehicles controls... The transmition(being Electronic controled vs Vaccum) detectes a surge or drop in electrical and put the trany into what Chevy calls "FAIL SAFE MODE" only allowing your vehicle I think it was 2nd and overdrive. Now check this out! A few days ago my heater blower no longer works... check the fuses... the relays... the resistor... the motor and nothin is wrong with any of them! Seems this ignition switch is a master of headaches and confusion! SOoooo needles to say when I got the time to replace this damn ignitino switch Ill be sure to let you all know if my heat is part of this Ignition Switch nightmare!