I have a 1994 LT1 coupe with 117K miles. In July on a 95 degree day, I had been driving on the highway for approximately an hour and 15 minutes. My security light then started flashing after which the SYS indicator started blinking on the speedometer. Within about 30 seconds my instrument cluster simply turned off - the car was still running just fine (mechanically). I pulled over and checked my gauges - all the analog gauges were working and within normal range, including temp. I turned the car off but my high beam indicator was on and flickering. After confirming there did not appear to be a dead short and the car was in fact not on fire, I turned the key on - the instrument cluster lit up, but when I turned the key to start, the instrument cluster went dark and the PARK and BRAKE lights illuminated. I waited about 20 minutes thinking it might be a heat problem and allowing it to cool would help but had the same results. I then called AAA and waited an hour for a tow. Unfortunately, AAA had told the driver I was a Chevy K-10, so he had brought a tow truck instead of a rollback, so I figured I'd try one more time. The car started without incident and with a normal appearing dash, so I attempted to drive the car home - after about 8 miles I had an exact recurrence of the problem - Security light, then SYS indicator, then a dark instrument cluster except a flickering high beam light.

I had the car taken home and when I tried then, it started and I was able to drive it into my garage. I didn't have time to do much with the car at that point, but when I went to start the car and do some checking the following day, the battery was stone dead - the courtesy lights wouldn't even come on. I put the battery on charge but didn't have much time do anything with the car for a couple of weeks. When I did, the car started up no problem, ran fine and I coudn't reproduce the problem. It hadn't been nearly as hot, again leading me to believe it was a heat related issue to begin with. I drove the car daily for almost a week until one morning (when it was about 50 degrees) the exact same thing happened again - Security light, SYS indicator then a dark cluster. I was only a mile from my house (arguing against a heat issue) so I turned around and brought it home - turned the car off in the garage and since that time, anytime I turn the key on the dash will illuminate but when I try to start the car the instrument panel goes dark and the PARK and BRAKE indicators light.

I have an FSM and have tried troubleshooting but I haven't really been able to get very far. Obviously I have an electrical problem - I think the connection between the instrument cluster and the car not starting may be in the antitheft system, which might also explain why the Security light has always been the first indicator of the issue. I'm wondering if I need a new dash, or if this could be a bad ground, but have had a hard time trying to track it down. Has anybody seen this before or could lend any suggestions?

Thanks in advance.

Matt


P.S. Something I forgot to mention - the Check Engine light has not come on through all of this. I did pull the codes and the only thing I got was an H16.

 

I hate to just bump this up, but I'm really at a loss....anybody have any suggestions at all?

Thanks again
Matt

 

I feel for you, but thankfully your problem hasn't happened to my 94, however, I may recall reading something similiar related to the security module or whatever it is mounted in the compartment behind the driver seat.

Other thought, it might be a ground that's slightly loose and the extra heat or vibration or moisture is causing the problem.

Two important ground points -- 1. behind kick panel in driver's foot well (by your left foot). 2. Bell housing, driver side, forward of the clutch slave, where bell housing bolts to engine.

Another thought -- given the dead battery the one time -- any chance the battery is the problem -- older than 3 yrs, or a gell or other non-wet cell type which tend to die without warning..

or, the battery cable/connections?

 

CLEAN the cable connections, and TIGHTEN the cables at the batt posts.