electric issues

[shaunmorris]

Hi,
I was wondering how many of the cars electrical systems are linked to the alarm, I have number of electrical issues, but before I start going through them I thought I would ask the question as currently my 1997 4.2 has no key and I am running it through a hot wire on the immobiliser. this means the car alarm goes off every time the battery is connected. The alarm will be rebuilt in the very near future, but I want to start work on the mirrors, horns, fans etc if there is no connection.

Cheers

[Penelope Stopit]

Those circuits you have listed are not connected to the immobiliser

[RUSSELLM]

Probably best to start on One item, and see where it takes you.

If that list, i’d start with the horn

Talking of horns, I finally got round to looking at mine the other day, and was suprised to find there’s wiring there for Two of them.

[shaunmorris]

I suspected these thing would not be connected, so i will take a look at the horns, seems like a good place to start, it has two fitted but completely silent, I can hear the relay click in the boot so suspect the problem is at the front end.

[Byker28i]

The immobiliser kills power to the ecu, fuel pump and starter only, so all other circuits should be ok.

When you say no key...

[pmessling]

The horns at the front are very venerable from the elements so doesn't surprise they don't work.

Incidentally my 04 car has two.

Whilst you in the area the loom is wrapped up, there is also a thermistor for the weather warning light, good time to replace it.

[RUSSELLM]

Mirrors and Horn, by the way.... see if your Wipers and Radio are working.

I seem to recall, that contrary to the fuse box diagram in my owners manual, the knackered wiper motor used to take out those other Three items.

[shaunmorris]

Wipers and radio are fine
The horns work as I have tested them with a battery
There is a good earth connection
And when you press the horn button, I can hear the relay click in the boot
Starting to scratch my head a little with this

[Penelope Stopit]

shaunmorris said:

Wipers and radio are fine
The horns work as I have tested them with a battery
There is a good earth connection
And when you press the horn button, I can hear the relay click in the boot
Starting to scratch my head a little with this

Keep scratching, that's what the jobs all about

Take another step in the right direction, you've proven the button is operating the relay, now test at the back of the fusebox to see if there is an output from the relay to the horn wire that exits the fusebox, I take it you have checked the relay is ok

[RUSSELLM]

shaunmorris said:

Wipers and radio are fine
The horns work as I have tested them with a battery
There is a good earth connection
And when you press the horn button, I can hear the relay click in the boot
Starting to scratch my head a little with this

Without seeing a diagram, I’m guessing you’ve a good permanent ground on one of the wires at the horn ?

So you’re looking for a switched 12v positive on the other wire.

The relay for the horn... check the common pin, has a 12v+ on it. If it has, at this point put a little wire link between the common pin in the fuse board and the normally open pin. You should now hear the horn sound, if you do, then you’ve a knackered relay.

If not, then you’ve got to check the wire from the normally open side of the fuseboard, has continuity to the wire at the horn. If it hasn’t you’re looking for a broken wire from fuse board to horn, or an inline connector disconnected.

[shaunmorris]

Russel, thanks again, I fitted a new relay just to be on the safe side, but still nothing on the horns, good news is that the fans are now working, the plug that fits into the temp sensor was shorting itself so flushed it with cleaning fluid and success the fans now run.

[shaunmorris]

Finally the horns work, turn out to be a poor connection to the back of the fuse box