Pump is running ever 5 minutes. The heat in the

the heater element is in the pump housing and needs the pump running so that the heated water is circulated to get it all hot
with no pump operation all that is getting hot is the pump housing area and that will burn out the element

If your hot tub is running but NOT heating then you need to look at a couple of things.
First, on the topside, is the heat indicator light on?
If it is on and the tub is not heating then the temp sensor or the high limit sensor is not working and need to be replaced.
US Parts Center

This sounds like your motor is going out. When they get noisy and run really hot is when they go out

Rod
US Parts Center

Contact Maryland Hot Tub Repair @ 410-304-2463 or see their web site www.maryland-hottub-pool-spa-repair.com/ they specialize in Jacuzzi Sundance Service.

Most hot tubs have a freeze protection that will lock you out and run the pumps full blast with no heater if the temerature is under 50 degrees F.The circulating pumps create heat until the water temp is above 50 degrees, and then the heater will come on after that.
Hot tubs do this to protect themselves and it is normal operation.

first thing you need to check is if the reversing valve is working you maybe running your A/C with the heat strips on depends on the t-stat your using some heat pumps will bring the strips on with a high degree difference in setting and room temp .

1- turn t-stat to heat set temp 10 degrees above room temp if you have a programable t-stat it will have a time delay on it allow to for the outdoor unit to come on 2 to 5 minute usually .
2- walk around to the outdoor unit when it comes on feel the big line the insulated one and see if it is hot or cold let it run for a 5 minutes peel back the insulation and gently grab the line with your hand it maybe real hot so be careful if this line is hot then your heat pumps is working mechanically and if it is just warm then you may need the charge topped off

there are so many different option's from this point i will need to know the findings of this test first thanks : Michael

check to see that the flow switch is working properly, it may not have enough flow on low speed to allow the heater to turn on. Make sure your filter/s is/are clean. If you have a pressure switch instead of a flow switch, it may need to be adjusted or replaced.

it may take longer to heat to desire temp. if nothing chang have you adjust the temp higher . if everything check ok check high limit switch next to the control box ussualy red bottom push soft in

I replaced the upper control panel, and that was the problem.

when you removed the water pump, did you disturb the timing in anyway ???