t1i shorting lenese?

has any one had this problem or know of something that could cause this problem?
this is happening on a t1i it has battery grip. 2 lenses are now useless. meaning they would cause error 99 and/or would not focus at times.
could defective after market batteries cause it. i know one of the batteries is shot. let me know if anyone has seen this. im trying to pin point to source before i send it to canon for repairs. sugestions are welcome.

Would these happen to be older Sigma or Tamron lenses? Some are not compatible with later Canon camera models.

one is an older tamron that worked for years on the camera. the other one is a canon lens.

Can you test to see if the lenses work on a different camera body to try to isolate the problem.

I haven't had problems with using worn out Canon branded batteries. I usually just put the poor batteries together in the battery grip where two worn out batteries will still work decently if there are two of them.

Remove the grip. Put in a fresh battery and see if your problem persists.