My 401k is over 50,000 in equity with a 9000 loan already attached, will this effect approval on another 12000 loan

First its not a good idea to piggyback your question on someone else's. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

That depends on your plan provisions. Some plans allow multiple loans, others would require you pay off the existing loan first. Others might allow consilidation. Talk to the plan administrator.