How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask TheHotTubGuy Your Own Question
TheHotTubGuy, Hot Tub Repairman
Category: Pool and Spa
Satisfied Customers: 448
Experience:  20yrs. experience repairing all brands of hot tubs.
Type Your Pool and Spa Question Here...
TheHotTubGuy is online now
A new question is answered every 9 seconds

I need some help on my 2001 Vanguard Hot Spring Tub

Customer Question

Hello I need some help on my 2001 Vanguard Hot Spring Tub
Submitted: 2 years ago.
Category: Pool and Spa
Expert:  TheHotTubGuy replied 2 years ago.
My name is*****'ll do my best to answer your question and resolve your issue.

Please explain your problem/problems in detail, I am not sure what exactly I'm troubleshooting. That is quite a list of new parts....

Thank you.

Standing by,

Customer: replied 2 years ago.

We are moving and our new tenants want the spa and are willing to pay for the up keep. So we decided to "fully" fix the tub. there are very few hot tub repairmen around here and the ones available are outrageous expensive. This led to me learning more about hot tubs than I want to know. I have replaced everything but the shell and never had a problem for 11 years till now. The control panel was working erratically. The only button that worked was the "light+" and that actually turned the jets on and off. No temp adjustment, no light, aux panel non-funtional etc...So I went all out and replaced all of it and it is still not working.

The limit ok light is green but the control unpluged is still blinking

Expert:  TheHotTubGuy replied 2 years ago.

Sorry for your troubles.

It sounds like your original issue was in the control head or main IQ circuit board.

The flashing or solid control unplugged light is not a good sign. I have not seen this led flash...usually it is off (good) or on (problem). Installing a new control head is not rocket science, however, it can be a little picky getting it attached to the face panel properly. The torque of the mounting screws can make the buttons difficult to press or sometimes not work properly. This can cause issues, but will not cause the control unplugged led on the board to light up.

You have a mismatched board/control head, a bad ribbon cable between the two and/or a bad connection, or a bad circuit board. These systems will not operate without a working control panel plugged into the board. When the control unplugged error light is on, often it is a 50/50 guess as to what part is bad; the circuit board or control head.

I suggest you look over the ribbon cable closely for nicks or damage. If the control head came with a new ribbon cable, double check the connections at both ends. These parts must match to work correctly. It seems like I remember that Watkins was no longer providing replacement control heads for the 01 and new control heads required a new matching board to work correctly? All part of streamlining all there IQ systems across product lines. may have had a bad control head and now the replacement is not compatible with the original circuit board. Or, the control head may be for different model years and not compatible with the original board. They all look alike. Or, you may have had and still have a bad IQ circuit board.

If you send me the part number of the control head you replaced, I will double check that it matches. However, I do remember there being an issue with new stock working with early 00-02 IQ boards. At the very least, I think it's noted that it's still possible some will work, but not all.

Standing by,

Customer: replied 2 years ago.

I came to the same conclusion that is was the control head or the motherboard, so I replaced both with the latest "upgraded" models.

The control head is WM-71905 Auxiliary Panel 4 Button 1998-2003 Hot Spring [Color:Green] and the Motherboard, IQ 2020, Hot Spring, Tiger River, Limelight, 2001-2009.5 PN 77087 with the "newer" WATKINS Control-Stat & Hi-Limit Thermistor '02-Current PN 39530 & 39525

It came with a new ribbon and that seems to check out pretty good. I do not see any nicks, bends or damage. Are you saying the control head I bought may not be compatible? If so I don't know what else to buy. The entire electronic system is new, and it should work as if it was a new tub. Is there a way to troubleshoot and know for sure? The same issue is happening even AFTER every control head, aux panel and motherboard has been replaced. That is the perplexing part. Since I bought these from Watkins dealers online, sending back a part to try and see if it was the cause could be a very long and tedious process. There has got to be a way to diagnose without parts trial and error. The chances of one of those new parts being faulty is slim, but it could happen. - Kris

I did some more research and I think there is something called a " pressure by-pass jumper" that needs to be installed before the heater will start heating. I don't know if this will affect everything or not. My board does not have this item.

Expert:  TheHotTubGuy replied 2 years ago.

I missed that you replaced the board as well as the control head. Sorry about that, I was thinking you were still using the original board and had replaced everything else.

I'll check those parts for compatibility in the morning. Let's focus on the IQ wiring, power jumpers, and program jumpers.

Please send some pictures of the inside of the control box. I will need to enlarge them and double check the wiring at the heater board, the power jumpers, and be able to view the entire main circuit board to see the program jumpers.

The pressure switch by-pass jumper is necessary on the newer model systems starting around 08. Your new board my need it installed or not. I will be able to tell from the pictures if you do. This will not be the reason the control unplugged light is on. There is something mismatched or hopefully it is a jumper setting causing the problem.

Here is how to send pictures:

Standing by,

Customer: replied 2 years ago.
Customer: replied 2 years ago.
Customer: replied 2 years ago.
Customer: replied 2 years ago.
Expert:  TheHotTubGuy replied 2 years ago.

Good morning,

The pics came through great.

Okay.....Lets try some things. I see you are missing the bracket around the heater board and the strap that goes across the board that holds the cover in place. You need to reinstall those brackets.

Your system must be grounded properly. It is necessary to have the bracket around the heater board, the main ground lug will screw in where the bottom screw for that bracket's marked ground. This grounds the heater board and lug to the metal strip on the box of the IQ box. The spot you are using for the ground is for the heater ground. must have the main board grounded properly, also. You are missing the grounding screws that hold the IQ board in place. There are 3 of these holes across the bottom of the board. I can see a broken off screw in 1 of these holes. You will need the proper size screws to mount the board to the metal ground strip behind the box.

Please disconnect all the equipment from the board except for the circulation pump. Leave the power, control panel, and sensors connected. Unplug the aux topside, also.

After the board is mounted/grounded and you have just the circ pump connected, turn the 20 amp breaker back on. You can leave the heater connected, just be sure to leave the 30 breaker off for now.

Update me on what happens. If you feel pics will help, please include as many as you want.

The program jumper and wiring look correct. You ARE missing the pressure switch jumper on the board.

This should not cause the flashing control unplugged but will make the power and ready lights flash on the control panel if not installed.

Standing by,


Customer: replied 2 years ago.

I did exactly what you said, in this 95 degree heat and nothing. I was told I can manufacture a jumper for that heater pressure pin. There are three pins there and I am not sure which two to connect. Anyway, this is beyond frustrating and surreal, ALL the parts are brand new and within the new conformity, yet the tub does not work. - Kris

Customer: replied 2 years ago.


I've been on the phone with BackyardsPlus and we fixed the problem. First, the jumper can be manufactured with a small piece of wire connecting the left and center pin of the pressure relay switch at P34. The most important item was critical for the tub to ever work. P13-P12 connecting wire was not installed. As soon as that was fixed the entire tub came to life and the new equipment is working as new equipment should - perfectly. I wish you identified that, and I know you tried and were working on several solutions, but when I looked at the pictures, you can clearly see that jumper missing. I won't rate you at all, even though I'm sure I'll get emails reminding me a thousand times. I will terminate my monthly subscription and request my 41.00 back. Thank you for your time and save this as a learning tool. - Kris

Expert:  TheHotTubGuy replied 2 years ago.

Yep, I missed it. Easy to spot once you know.

I do prefer having my own eyes, hands, and meter on the tub I'm troubleshooting. I definitely won't miss that again. Odd though, I never seen a control unplugged LED flash, just either on or off.

Thanks for the update and not blasting my ratings, I do appreciate that. I was hoping for a good outcome and I am glad it's working! It was bugging me, too.

Best regards,