Anyone familiar with temperature control boxes for swamp coolers?

Question:I just installed one so my swamp cooler will go on and off automatically. It has been working great for the last 3 days, however this morning I started hearing a high pitched squeel that sounded like it was coming from the pump (I have a down draft system so the units on my roof). This only happens when the control box turns on the pump so it can run for 4 min. before turning on the fan. It also only squeels for about 10 seconds or less. Could this just be the pump going out, or is it related to the control box? I did double check the wires that I connected for the control box and everything seems to be ok there, but again maybe someone has an idea.

Answers:
Either the pump is going bad or possibly an accumulation of debris in the sump is causing a problem.