Mechanics

DOES A BAD IGNITION SWITCH TURN ON THE SERVI

1997 GMC Jimmy

Computer problem
1997 GMC Jimmy 6 cyl Four Wheel Drive Automatic 215000 miles

Lately Ive been having the engine light come on. Then I turn it off be taking out the ECM batt fuse and the light stays off for about another week. Just today the light came on but after the resetting procedure, it stayed on and I made sure the gas cap was on properly and it still did not turn off the check engine light.

Also, sometimes I have troubles starting the truck whenever the dashboard lights DONT come on so I keep turning back and forth the key until I get the lights to come on. And sure enough it starts!

Also, sometimes after shutting off the ignition, the key is stuck and prevents me from turning the key all the way back and taking it out. But I can still turn it forward and start the truck. I usually fiddle around with it until it decides to come out.

Is this all because of a faulty ignition switch?
Avatar
DipstickJIMMY
December 1, 2009.




Unlikely.

not being able to turn the key is most likely a problem with the lock, or the transmission shift interlock, not the switch.

check the codes and lets see what we got.
http://www.2carpros.com/dia/how_to_scan_trouble_codes.htm

Buddycraigg
Dec 2, 2009.
Its a Center Shift Console.

The truck cranks but wont turn over if the panel lights do not come on.
Is that not related to the IGN switch?

I will get the code reading ASAP!
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Tiny
DipstickJIMMY
Dec 2, 2009.
I think you have 3 different problems.
Or possibly 1 problem and then 2 more that are related to each other.

1, check for the codes.

2, when you turn the key and the dash lights do not come on is a problem with the ignition switch or the mechanical linkage between the lock cylinder and the switch.

3 the safety device that keeps you from turning the key to the lock position unless the transmission is in park has a problem,
a problem with the mechanical linkage between the lock cylinder and the switch,
the lock cylinder.

Buddycraigg
Dec 3, 2009.
It makes sense now that u explained it.
I will find sometime on the weekend to salvage a lock cylinder and also a ignition switch.

But I should have you some codes tomorrow night.
Thanks!

Tiny
DipstickJIMMY
Dec 3, 2009.
Don't get a used ignition switch, that may be your problem.
Spend a few extra bucks and get a new one.

Buddycraigg
Dec 4, 2009.
Got the codes, and it is basically all the solenoids that needs to be changed as I was told.

PO740 - Torque Converter CLutch Solenoid Circuit Open

PO753A - Shift Solenoid A Electrical

PO758D - Shift Solenoid B Electrical

P0785 - Shift/timing Solenoid Malfunction

P1860 - Manufacturer Controlled Transmission

Can you give me an estimate on how long a transmission shop would take to do this. And the cost? Thanks

Tiny
DipstickJIMMY
Dec 5, 2009.
Hmm interesting. I was reading through some topics in your forums and I ran across something that was posted by one of your technicians.

" TIP
Malfunction indicator lamp (MIL) on, trans stuck in 2nd or 3rd gear, instrument cluster inoperative (diagnose & replace ignition switch
if necc). See bulletin #01-07-30-002. Techs in field report IGN switch failure is common & may cause multiple symptoms with trans, IPC or other IGN feed circuits. (DTCs) P0740, P0753, P0758, P0785, P1860 may be set.

Most likely cause of this condition may be a loss of power to the transmission on circuit 1020.

To verify, with the ignition switch in the run position, test for battery voltage at the appropriate fuse listed below.

1997 s/t trans 24
1998-2003 s/t (old style) cluster 11
2002-2003 s/t (new style) ignition 0
1997-2000 c/k (old style) trans 20
1999-2003 c/k (new style) ignition 0
1997-2002 g-van trans 20
2003 g, h-van ignition 0
2003 H2 ignition 0
After IGN switch replacement, VTD (theft deterrent) relearn must be performed " I took my jimmy to a transmission shop yesterday and they got me worried because they looked at the codes and said its not the solenoids I need to change but its an internal problem and that I would need to get a new tranny. Then I ran across that forum response and it got my hopes up that its as easy as changing my IGN switch. So are the transmission guys BSing me?

Tiny
DipstickJIMMY
Dec 6, 2009.
I don't think so, they are just going with the best of their knowledge. They specialize in transmissions repair, not general service.

You've got a lot of things pointing to the ignition switch being a problem.
The most logical step would be to replace it.

Buddycraigg
Dec 7, 2009.

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