RX400H Horn Relay Location

[Lexusnumerouno]

Hi, I have a faulty horn on my Lexus RX400h 2005 - I have checked the fuse and all appears OK, it has been suggested that the Horn Relay could be at fault but I don't seem to be able to locate it. Various websites offer no help either - does somebody know where the little blighter might be please.

[Herbie]

This is what the workshop manual says:

[Lexusnumerouno]

Thanks Herbie, I managed to find the relay set, the relay shown in the manual diagram says on the plastic cover 'RDI Fan No.2' - I wonder if this is a dual function relay? I do have a couple of photo's I took - I'll see if I can upload them to this forum - thanks for your help.

[Lexusnumerouno]

[PCM]

When mine stopped working it was a loose earth wire I believe ... 

[Lexusnumerouno]

Hi again - does anybody  know if the diagram posted by Herbie above points to the relay image (r/h photo) which is labelled on the underside of the plastic cover as RDI FAN No2. Is this a multi function relay that will also operate my Horn.

[Herbie]

I honestly don't know, but pull it and test it anyway, see what results you get.

[impero]

On 7/15/2019 at 4:55 PM, Lexusnumerouno said:

Hi again - does anybody  know if the diagram posted by Herbie above points to the relay image (r/h photo) which is labelled on the underside of the plastic cover as RDI FAN No2. Is this a multi function relay that will also operate my Horn.

Hi there. Have you discovered if the relay is used by another device ? If yes, would you be so kind and share with us ?

I am curious because my RX400h have a problem with horn, but kinda opposite situation compared to your situation.

I mean my horn ring continuously and i was forced to take of the fuse from the panel.

I checked the relay and it seems to be in order.

But as you already said, the fact that it could be in use by another device makes me think if that device could be responsible for this situation.

Cheers

[impero]

Ok i found out the source of my problem.

The relay indicated in the service manual for my LexusRX400h was not for HORN.

Anyway i found out using the repair manual for Lexus RX400h, what is the circuit diagram for my car, and step by step i discovered the problem.

It was a circuit board situated near the fuse box - that contains a lot of electronic circuits and relays (one of them is for HORN ).

I just swap it with another board and all was solved.

I attach pictures with that circuit board

Hope that my problem will help others to solve their problems also.

Cheers

On 7/15/2019 at 4:55 PM, Lexusnumerouno said:

Hi again - does anybody  know if the diagram posted by Herbie above points to the relay image (r/h photo) which is labelled on the underside of the plastic cover as RDI FAN No2. Is this a multi function relay that will also operate my Horn.

Hi there. Have you discovered if the relay is used by another device ? If yes, would you be so kind and share with us ?

I am curious because my RX400h have a problem with horn, but kinda opposite situation compared to your situation.

I mean my horn ring continuously and i was forced to take of the fuse from the panel.

I checked the relay and it seems to be in order.

But as you already said, the fact that it could be in use by another device makes me think if if not that devices fault for this situation.

Cheers