In article . com,
" wrote:

Back in the spring, my 1987 Carrier Vertical GFA system wouldn't fire
up. I saw that after the HSI didn't come on, it went into shutdown
mode. I figured I'd replace the HSI before fall.

Now, $30 later, the new HSI still won't fire up. The draft induction
motor starts, but no HSI. Could this problem be in the control module?
Is there any suggestion for giving it another DYI repair before I call
in a pro? Any links? Thanks.

Not really. There are many variables to the sequence of operation of
your furnace, that you need to check.

You can keep on changing parts, until you find out what it is that is
causing the problem, and even after you have replaced everything in the
furnace, you might still have the same problem.

I would call a pro, since furnace repair is really not a DIY repair.