Hello I'm having a problem with my 2005 c6 manual trans. Basically at night when I get in it press the start nothing happens. It does this more often than not. The next day I can come back to the car and get in and it fires right up no issues at all. Sometimes I use to be able to disconnect the battery for 10-15 and then it would start but that only worked about 50% of the time however that doesn't work anymore. It has done this for over a year now with multiple different batteries. The current battery is an optima red top less than 3 months old. The car stays on a battery tender 99% of the time and doesn't seem to have the issue when getting in when it's been plugged in HOWEVER i seem to always get in it while the sun is still up and it's day light out. i can drive to have dinner and by time i come outside and it's dark get into the car no start. If i take the top off of the crank relay (43) and push it together the car will turn over but won't start. (Had someone hold the clutch in aswell) I've checked all relays and none are corroded and even tried different relays. I took the bottom of the relay panel apart and check it everything seems fine there aswell. Ive cleaned all of the battery grounds,) I've tried both keys and even replaced batteries in both keys with no luck. I did have the colum lock issue and bought the bypass for it a while back. Not sure if that could be causing it but I'm not receiving anything on the dash. Please someone help or send Dano my way!

 

Well if you can jump the load contacts if the crank relay that part of the starting system is good…battery terminals are clean and tight ??…do you have a 12 volt test light and know how to use it ??…if so you can test the “control” side of the crank relay…do you have a scan tool preferably a factory level or comparable aftermarket one ??…makes checking the “inputs” to the starting system much easier…even with a code reader you can at least see if you communicate with the engine computer as sometimes these no crank no start can be a communication issue…ECM, BCM and RCLDR all have to communicate with each other for the car to start…there are too many variables for this and will not be a “silver bullet” !!…cleaning all the grounds is a waste of time unless the ground is part of the starting system.

 

 

There is a TSB but don’t know if it applies to you and your battery…the FIRST thing is checking the battery…because it’s fully charged doesn’t mean it’s good.

 

Do you think it might be the ignition switch.

 

have you tried resetting the BCM by unplugging and reconnecting.

 

the terminals are new and tight and I have a pretty nice code reader and test light. On the reader I'm not finding anything out of the ordinary. Today though however when I first got in the car didn't want to start and had a check engine light on I plugged the reader in and it said that their wasn't any codes. So I hit clear and then The car started right up that's the first time that has happened.

 

no I don't think so because it goes through the full start sequence when I press start IE the dash going dark for a few seconds

 

Odd the MIL was illuminated with no codes…well if it’s not starting let us know…I’ll post a few things to check with your test light a little later..we will see if the RUN/CRANK relay and if CRANK RELAY 43 is getting a control signal….do you know how to read a wiring diagram ??

 

it's done this with 3-4 different batteries because that was what I thought was the initial culprit.

 

Here is the OEM wiring diagram !!

 

You should be going through that many batteries…you sure you don’t have a parasitic drain taking these batteries out ??

 

i don't drive the car often because of the issue and it would get unplugged from the trickle charger and me not realize it. Or a family member would move it and forget to put it in reverse after moving it

 

I don't drive the car that often due to the issue and it would get unplugged from the trickle charger without me realizing it or a family member would move it and not put it in reverse after moving it.

The problem didn't happen tonight so I didn't get to check anything. But do you have any suggestions for things to check when it does?

 

With this being intermittent I'm thinking this may be a faulty clutch pedal switch or a pin fitment issue at the connector when it is not starting...now if you can remove the connector and find a thin paper clip and bend it into a U shape and insert it in the connector we can bypass the switch and see if the car consistently starts...you just have to be VERY careful that the car in in Neutral when starting since you are bypassing the switch...to see if the switch is bad use the ohm meter function of your DVOM and place it across the switch terminals and see if you have continuity every time you push the clutch in...if bypassing the switch doesn't work or the switch contacts are good we can see if the RUN/CRANK relay is being energized so we can check that at the clutch switch also...connect test light to a GOOD ground like the door hinge bolt (find a hot fuse at the BCM or use the accessory port in the center console to verify test light works)...probe the PINK wire at the clutch switch as you try to start the car...if the RUN/CRANK relay is working the test light will illuminate...ii that relay is working and we can verify the clutch switch is good the CRANK RELAY #43 should receive power...if you had a good scan tool you can see the inputs like the clutch switch "Applied/Released" and ignition switch by looking at the "Crank Request" data PID....and remember every time the battery goes dead and if you are able to recharge it its service life is greatly diminished....and it's harder to recharge or even charge an AGM battery at all if that's what you have...I'd say about 40% of the cars whether Corvettes or other cars I diagnose down here in Florida need batteries....I always start any diagnosis with a battery check.

 

Thanks boss next time it does it I'll give it all a try unfortunately with it being intermittent it's just a waiting game. The current battery has never died on me. Pretty much if they went dead once I'd swap it with a new one that's anlso why I've went through so many lol And oh nice I'm actually in north Florida myself!