Annoying buzzer when braking when towing

[MyOpinionIsWorthless]

Has anyone had the experience of a buzzer going off every time you apply the brakes when towing in a Prius?
 

feels like I’ve been pranked by Hammond and Clarkson. 

[TonyHSD]

Buzzer from the e pump when pressurise brake fluid for the rear wheels? If this is what you mean I can hear that sometimes more without towing just with normal use 

[MyOpinionIsWorthless]

34 minutes ago, TonyHSD said:

Buzzer from the e pump when pressurise brake fluid for the rear wheels? If this is what you mean I can hear that sometimes more without towing just with normal use 

Nope definately sounds like a sounder buzzer. Only when trailer is attached. Not under normal driving. 

[QuantumFireball]

I'm not too familiar with towing wiring harnesses but I know they may have a buzzer to tell you the indicators on the trailer are working (required in the UK?) - maybe it's been wired ubikways and is also/only buzzing for the brake lights?

[Sooty]

Towing?

Prius is not classified in UK for towing.

I'm sure it is illegal to tow a trailer in the UK with a Prius.

[QuantumFireball]

2 hours ago, Sooty said:

Towing?

Prius is not classified in UK for towing.

I'm sure it is illegal to tow a trailer in the UK with a Prius.

Gen 4 Prius (FWD version) had a towing capacity of 725 kg, nothing illegal here.

[MyOpinionIsWorthless]

8 hours ago, QuantumFireball said:

I'm not too familiar with towing wiring harnesses but I know they may have a buzzer to tell you the indicators on the trailer are working (required in the UK?) - maybe it's been wired ubikways and is also/only buzzing for the brake lights?

Yes only on braking. No sounder for indicators just the hypnotic click click click ….. click. 

[MyOpinionIsWorthless]

6 hours ago, Sooty said:

Towing?

Prius is not classified in UK for towing.

I'm sure it is illegal to tow a trailer in the UK with a Prius.

Nope. Rated for 725kg since 2016

[Sooty]

16 hours ago, PaulDM said:

Nope. Rated for 725kg since 2016

Ok, I stand corrected.

I know the Gen 2 and early Gen 3s are not allowed to tow so assumed it was across the whole range.

[MyOpinionIsWorthless]

On 7/14/2021 at 11:34 AM, Sooty said:

Ok, I stand corrected.

I know the Gen 2 and early Gen 3s are not allowed to tow so assumed it was across the whole range.

Absolutely true and I agree with your analysis. That’s why I upgraded my gen 2 to a gen 4. Also the gen 4 is still not approved in the USA. Some guys on a sister forum are fuming they can’t tow in California with a gen 4