Legacy Central Locking Puzzle - FIXED :)

[Guest 98legacy]

The car is a 1998 UK 2.0GLS (non-turbo) Legacy Wagon, RHD. I believe it is US built as there are lots of Canadian, US and Mexican components on it.

The central locking is only either key operated from outside, or triggered by the inside lock on the drivers door.

There is no locking solenoid in the driver's door, just a switch which presumably then triggers the rest of the system somehow.

There is no alarm or keyless remote. There is a factory-fitted immobiliser though.

I have a US version Haynes manual but the wiring diagrams don't seem very relevant to the UK car.

 

(edit:- see 10 january post - they are relevant but incomplete)

 

Symptoms:

 

Ignition Off and unlocked:- Nothing happens, as expected

 

Ignition off and locked (either from inside or outside as above):-

The driver's door locks (mechanically) and triggers the switch. If any other locks are unlocked they lock immediately, but then continue to receive lock signals at regular approximately 5 second intervals thereafter. This can be heard as a ticking noise and is to all other doors and the tailgate. If I leave the drivers door locked when this is occuring, and then unlock any of the other locks manually, they lock again on the next "pulse". The only way to stop this is to remove the fuse or leave the car unlocked.

 

I have noticed that the "pulses" seem to occur at the same interval at which the red flashing immobiliser light on the dash comes on.

 

Ignition on:-

The digital clock often loses illumination when the system is unlocked, but sometimes (intermittently) comes on again when the driver's door is locked. It doesn't look as bright as usual though. The system works when the clock is illuminated, but doesn't when it isn't.

 

Engine running:-

Rarely, when the clock is not illuminated, there is a two tone beeping sound, apparently from the rear passenger (left) side of the car. This seems to energise the clock and the locking again for a while.

 

The problem started soon after I replaced the passenger (left) side exterior mirror, which of course involved taking the door trim off.

 

All the other electrics on the car seem to work OK.

 

 

Help required please:-

 

I guess this may be a grounding problem of some sort? Any pointers please?

What is the source of the two tone beeping sound?

There is supposed to be an ECU and /or a timer unit for the central locking. The only timer module I could find turned out to be for the rear window defogger. Can anyone tell me where to look for these units on this car and which it has?

 

Thanks in anticipation.

[Hondasucks]

I'm not quite sure on this, but since you mentioned the immobilizer light, maybe there is a malfunction in the immobilizer, because locking the doors would be a logical function of that component. You might try a dealer, see if they have a diagram for it.

[Guest 98legacy]

I eventually found the central locking module but it was dry and clearly looked OK.

 

I hadn't noticed before, but the interior lights were also intermittent. When they gave up altogether (as did the clock, radio memory and central locking) that was the clue, as everything with the problem was on the same fuse. That fuse, however, was intact.

 

The problem was either a broken wire or bad connection, at first intermittent until it gave up altogether, somewhere between fuse 25 (as it's designated in the US Haynes Manual) and the radio memory, clock, central locking module and interior lights.

 

I think it was a combination of the intermittent fault and the electronics in the central locking module (perhaps a capacitor taking time to charge) that caused the confusing "pulsing".

 

I have fixed the problem by running a new wire from fuse 25 into the clock.

 

Incidentally, now I have waded through the wiring diagrams in Haynes they do appear to be applicable to my car. They're incomplete, though.

 

I think the two tone pulse was the radio searching for a station on the default frequency (because it had lost its memory) and alarming when it couldn't find one. I was hearing the alarm sound from the left rear speaker because that is how I have the fade/balance controls set!

 

All the messing with the mirror was nothing to do with the problem - just a coincidence.

 

Hope this helps someone sometime

 

Regards

Steve