general problems of the 1997 Chevrolet Blazer

97 Blazer with original low miles had engine stop both on and off the highway several times but it would start back up. In Jan while driving down the highway the service engine light came on and rpms went up. We pulled off and found the transmission was stuck in 3'rd gear. Also key would not release to remove. Errors came up p1860 p0785 and p740 that refer to transmission. The problem was not transmission but ignition switch contact block commonly called the ignition switch, it is the contact section and not the key or lock cylinder. This ignition switch had already been replaced once. Gm has a service bulletin #17006264 on the ignition switch and this appears to be a big problem across many years and models but no recall was issued. An ignition switch problem can cause engine to die, lights to go out and other problems but the contact for the transmission power seems to be a common failure point. I replaced the ignition switch and everything worked fine for one month and then the problem reoccurred with errors p1860 p0758 p0753 p0740 and p0785. I tested the ignition switch power from red/white to white wire and got no power when switch was on so the new switch failed. I tested by temporary jumpering a fused line to fuse 24 output and then transmission worked fine and the key released. I again replaced the ignition switch contact block under warranty and new switch worked fine except the errors came back on p0740, p0785 and p1860. Transmission worked ok though so I took the Blazer to a chevy dealership to check it. They reset code errors , checked wiring, connections and switch. The technician said my work was correct and everything checks out fine and he was not sure why codes came back. Now ok. I examined the original switch and there was no problem with contacts or wires evident. This could be a switch design issue or there is another issue causing this.

The 1997 and 1998 Blazer has an inherent defect in the valve body in transmission. Code 1870 found after vehicle is warm the transmission slams into second gear causing the rear wheels to loose traction. I was told the transmission most likely needs a valve body. The Chevrolet dealer and a very reputable transmission repair shop advised that the 1997 and 1998 Blazers are notorious for this inherent defect, and they have replaced the defective valve body with a larger one which fixes the problem. The dealer advised that there hasn't been a recall probably because no one has complained about the problem.