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Limp Mode = Failed Ignition Switch

23K views 10 replies 2 participants last post by  xPosTech  
#1 ·
97 Burb, K1500. I'v been dealing with an intermittent problem where my tranny looses power, goes into limp mode, gets stuck in 3rd, I loose my Speedo, RPMs, PRNDL selector light and get 6-8 tranny codes. Most of the time clearing the codes and turning the truck off n back on would solve the problem and it wouldn't happen again for a week or longer. other times jiggling the wires on the tranny combined with the above seemed to work. being intermittent made it really tough to trouble shoot properly. I figured the pink wire for pin E which carries 12+ to the tranny had to have a break.

then it became more of a permanent problem 2 weeks ago or so. I'v troubleshot it many ways. the fuse was good, had 12V. I went under inspected the wires, checked the voltage n it read 5V. I disassembled the harness quite a bit, thought I had a break in the pink wire, snipped it checked it n nope, back to 12V so I put that wire back together, soldered n shrink wrapped of course. checked it out with volt meter again, had 12 volts. I Giggled the crap out of the harness and couldnt get it to loose connection so I rewrapped the harness, plugged everything back in and resecured very well, put the shield back on and took it for a spin. well it wasnt fixed, 1/4 mile down the road I loose it again. bring it home and check the voltage on pin E and it reads perfect, giggle the crap out of the wire and cant make it loose connection. damn it!

So now I think internal harness problem, call up the tranny shop that rebuilt it, tell him whats going on and he says bring it in, if theres something wrong with the tranny he'll fix it for free even though its a few months past warranty, he dosent care. perfect. if its something else he'll let me know n go from there.

he puts the tranny on his computer and all functions of the tranny work perfectly as they should. plugs it back in and the truck fails to start. this only happened to me maybe 3 times over the last couple months and led me to replacing the ground straps. I never thought to tell him this as I thought I had fixed that problem, I also never told him I didnt have the gauges ect working, I just thought that was a sympton of the tranny loosing power, if you pull the fuse this happens... when I dropped the truck off and told him that last bit of info he suspected the ignition switch but would go ahead with the diagnosis...


so he gives me a call a couple hours later to tell me everything he done and the diagnosis is the Ignition Switch, got him to ball park the fix, he says $300 for the part and maybe another $200 for the diagnosis n repair. I declined the fix and thanked him for all his work.

go to google and the first video I see is for 97 gmc ignition switch list the symptoms as being exactly what was happening with my truck complete with every tranny code I have.

man do I feel like a dumbass!

now iv found a few replacment parts and holy crap they are pricey! range from $175 delivered to way more than $300!

anyways im blabbering on cuz im kinda ticked off... LOL. $100 For the diagnosis and a couple hours of work, I dont even think he billed me for the labour. so I learned something new today.

Cheers!
 
#4 ·
Who wudda think it? I wonder if that was one of the hidden fixes GM came up with so most people would have to take their truck to the dealer?

Spock would have said "Illogical, Captain. No one would design an ignition system that would interfere with something so simple as a transmission." "Aye Mr. Spock. They didna have to add so many functions t' a switch made f'only three!!" Scotty added.

Ted
 
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#5 ·
no shyt eh! explains why sometimes it worked when i restarted the truck and or had different symptoms. it had nothing to do with what i was doing but rather the switching mechanism. iv never had an ignition switch fail before so i really had no clue. iv read the 30 common 4L60E and went through actual tech troubleshooting guides. since the tranny was the only thing not working (mostly) I just didnt clue in. n ya a couple 3 times the truck wouldnt start, i just figured bad grounds, so i replaced those n then when it happened once after that i thought maybe its my scanner drawing power or some crap... but by continuing to try to start it, it would eventually and like nothing was wrong. grrrrr. haha

now trying to find the right part that will ship to Canada is a PITA. I dont understand why theres sellers on eBay.ca or amazon.ca that wont ship to Canada, isnt that the damn point for having the Canadian sites LOL. but I have found a few sellers on Ebay.com that do ship here and have a decent price. im looking around $180.

but would you know there are at least 6 different part numbers all different manufacturers and not just one common truck part number. sure makes finding the right one a nightmare and these switches are only for 97's Chevy or GMC Fullsize Trucks.

26061330, D1496C - Ac Delco
US-296 - Standard Motor Products
IS136 - Original Engine Management, (crafty name there eh, these are the cheapest and the one im buying.)
LS931 - Wells
1S6475 - Airtex
CS594 - BWD
 
#7 · (Edited)
well I called the local you pick junk yard. $30 for the switch n lock cylinder. I'm pretty excited to go see what they have there, shopping for some new rims as well but low on the list. haha I havent been picking through a junk yard since I was a kid.

so I continued to remove the switch from the vehicle to make sure I brought all the tools and that I knew how to do it. its a pain in the arse but I got it done without breaking anything.

the other day I tried to see if I could find and fix the problem... yes n no LOL I opened the mechanical side of the switch to investigate... once you open it 6 tiny springs, 6 swiveling contacts, the tumbler and a big round spring basically go flying. LOL. GOOD LUCK. there were burnt marks on the contacts so I assume after 20 years of functioning n arcing it finally produced enough hmmm carbon dust whatever its called to interfere with the connection. Well I cleaned up the contacts with electrical contact cleaner and attampted for like 4 hours to put it back together. good luck with that. LOL. I could get it back together but I was never confident that the tumbler was in the right spot and aligned properly with the spring so scratch that idea. it was worth a shot I guess, at least to investigate why it failed.

so today I wanted to really take it apart and see if there were any burnt wires or circuitry ect... there is no circuitry at all, its just wires, contacts, springs and the tumbler. crazy. nothing else was burnt anyways. maybe the tumbler was worn as well, its only plastic so prolly.

So Im guna take my chances on the $30 I pick a part ignition switch n roll the dice and order a new one for back up when I have some extra cash. Im heading out to get it in the morning. I hope to come back with good news.

heres some pics.

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#8 · (Edited)
All right so the verdict is in.... junk yards are fun :) LOL went in for the switch and came out with a bunch of stuff off a 97 sierra rw thats the same color as my truck. so I got the ignition cylinder but not the switch as it was cut up n spliced together. the floor matts, headlight switch, a cargo light switch, the little cubby to replace the cd player, and all that nobs off of the radio n thermostat. I should have grabbed some more things.

I found a good switch after searching through the entire yard looking for all the 97's that still had the steering column. LOL. I also found a brake controller! I think thats everything... $60

I came home n installed it then tested it right away and heck ya it works perfect! so I put everything back together and somehow broke an airbag wire at the connector. so took it back apart n soldered the wire back to the connector with a small jumper and all is well. put it all back together again and go for a spin n everything works perfect. WOOOHOOO Im a happy man. I called the tranny shop n thanked them.

the cylinder works perfectly nice n smooth and wont let me remove the key while the truck is running any more. LOL. that was convenient at times but if you shut it off you couldnt restart it without the key. the truck starts stronger and the interior lights seem brighter but i dont know maybe thats in my head. HAHA

and a bonus... the new key unlocks all the doors but the old one wont turn the ignition. lol. I was even just as pumped about that as I was about the switch.

Sweet Deal. Cheers!
Al
 
#9 ·
I forgot what they call it but if you have the keys with a square black piece of plastic on the key it contains a resistor that must match the lock cylinder. GM did that so they can use the same cut on several keys with the resistor defining which truck it will start.

Ted
 
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#10 ·
I dont have one of those keys but came across at least 1 97 with it, the ignition switch harness has an extra plug on it for that aswell. I didnt clue in right away as the key was in the cylinder sitting on the console... I had the column torn apart when I noticed the extra plug, pulled the key out of the cylinder and saw the chip... DAMMIT! that was the second switch I tried to harvest. lots of practice... I think im good at it now. LOL.

so I just got back from a good hour long drive. absolutly no problems whatsoever with the truck! but my stereo stopped producing sound... so gotta figure that out. I suspect the amp whetever that is.... I'll have to do some research n start a new thread.

Beauty eh.... Beauty!!!

have a great day guys!

Al
 
#11 ·
You probably had it cranked up and hit the overload. Turn it off for a few minutes and hopefully it'll be OK.

Years ago you could have ford keys cut to two vehicles. The double cut keys were so the key would work right side up or upside down. Now GM keys have the double cut. But it takes a little more to have them start two vehicles. Get past the key security and you can have one key start two vehicles. You just have to match the second vehicles security to the first.

Ted