lost12 volt supply!!

[turbineman]

silly question coming up i have no supply to heater motor or rhw switch.

checked fuses and connections on switches both good no 12v though.

there is obviously something i am missing to check as i assume there is something between fuse and switch help greatly accepted.

regards john

[Thurlo Squire]

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John

I would have a good look at the fuse box a these have a habit of giving up. Try taking a direct 12v feed from the battery to the wiring at the back of the fuse board to test the wiring from the fuse to the switches.

If the heater then works then you and you have 12v at the input side then you know the problem is within the fuse board.

Nigel

[turbineman]

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cheers nigel,

i have wippers horn lights just heater and rhw have stopped working.

should there be 12 v at fuses when ignition is on and engine running?

working perfect yesterday

regards john

[Thurlo Squire]

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John

See wiring diagram below which may help.

The HRW and heater motor are on the same circuit but not on the one with wipers etcand the power seems to come through an ignition relay which will be mounted in the passenger footwell. Maybe the problem lies with this?

Nigel

[turbineman]

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cheers nigel,

will try to swap relays im sure its simple if you know whats to look for,

thanks for the help.

diagram will help no end.

thanks again

regards john

[turbineman]

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am i right to assume all fuses inwiring diagramare in fuse box as opposed to in lines elsewhere

[Thurlo Squire]

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Yes John all fuses are in the fuse box. The Heater Motor fuse is second from the right when looking at the fuse box from the front.

Good luck

Nigel

[turbineman]

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cheers nigel,
had a root around and traced fault, as you first said fuse holder 12v in bottom
when measured on back of fuse but nothing on fuse itself.diagram really does help especially in colour nice one

one problem solved but what is common remedy if any or is new fuse box required tell me these can be serviced/fixed and done in situ.
regards john

[Thurlo Squire]

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Nearly cracked it John......

Check to see if the riveton the back of the boardbehind the dash passenger sideis loose or corroded as this carries the current from the back of the fuse box to the fuse holder at the front. If it is try using a punch over the rivet and gently tapping the punch to secure it more firmly.

Nigel

[turbineman]

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cheers nigel,

cracked fault pull of cables pushed /parked them on to a blade fuse 25 amp gave me radio and heater instantly will investigate when i get some time hopefully soon .

i installed a radio on friday it gave up the ghost on sat but ididnt mention it to start with as the suspect would have been radio wiring and i knew it was correct and worked perfectlyjob done withisolated battery when connecting.

thanks for your great help,hope i can return a favour sometime.

regards john

[turbineman]

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with dodgy connections on fuse holders can you drill out rivet and rerivet after cleaning.
problem i see is orginal rivets are copper, most rivets available are alloy,so
two different metals and electrolysis ithink or would small brass nut and bolt do any tried this or is it new fuse box?

[catlotion]

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sort of related - does anyone know if there's a switched supply(accessory position) in the heater/radio area? I'm adding an amplifier so I can retain the period radio but have an ipod connector...

[Thurlo Squire]

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catlotion wrote:

sort of related - does anyone know if there's a switched supply (accessory position) in the heater/radio area? I'm adding an amplifier so I can retain the period radio but have an ipod connector...

Why not use the radio supply as this should be running off the accessory part of the ignition switch?

Nigel

[catlotion]

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mmm - think mine's been bodged in the past as the radio is permanent live. there's quite a nest of wires back there!

Looks like I've got a date with my multimeter!

cheers

[Andy Rundell]

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catlotion wrote:

mmm - think mine's been bodged in the past as the radio is permanent live. there's quite a nest of wires back there!

Looks like I've got a date with my multimeter!

cheers

The permenant live may run from the feedsof either the glovebox lamp or the Lighter, often used for the constant supply to maintain radio memory etc. on more modern head units

As Nigel says youshould find the switched accessory feed for the radio around there somewhere.

........Andy