RRC - Alarm query - MotorsForum

Hi My RRC with a Vogue body circa 1986 came with an alarm unit operated by a single button squarish key fob marked Land Rover. There is a sensor at the top of each A-pillar inside and it has a siren unit bolted to the offside wheelarch under the bonnet. This has a large bunch of cables disappearing behind the dash.

This bunch of cables has 2 blade fuse holders in it before it enters the bulkhead which were empty.

Now my query.

I have put two 30amp fuses in these holders and everything appears to work . The siren goes off if I leave the window down and but my arm in. Also operating the fob activates the central locking.

None of the Halfords books nor the CD manuals that I have mention this alarm so I cannot find out the correct values of these fuses. I am reluctant to use the 30amp in case the circuits would not be sufficiently protected.

So if any of you good people could point me in the direction of some info on this alarm perhaps with a circuit diagram showing how it connects into the circuit diagram that I have, I would be very grateful.

At the least perhaps someone could indicate the values of these missing fuses.

Many thanks Peter

If you lack any better info.....

Kill the power to the unit, take the fuses out, bridge the connections with suitably robust ammeters (10 amp minimum, but with switchable lower ranges), & check the current when you turn it all back on with & without the alarm sounding. Put a fuse in to match or slightly exceed the highest current drawn.

You may have a problem reading the current draw from the central locking, as it's only a short pulse, & the meter may not read the full value.

I'd expect either 3 or 5 amp if all it's powering is a siren & an alarm system, though, possibly less.

The other way is to put a 1 amp fuse in, try it & if it blows, put a 3 amp in, & so on....

Crude, I know, but it's worked for me in the past on other similar jobs.

Tciao for Now!

John.