sgnas Posted April 6, 2013 Share Posted April 6, 2013 I've had an mot failure. No big deal all do-able. However, the seemingly easiest fix has me puzzled. As above "Brake fluid warning light inoperative". Now, rather obviously it wasn't going to be a bulb fault! I "think" it is due to the main earth bolt in the engine bay no longer being earthed. It's probably melted to the gearbox/engine/exhaust or something. I cannot find my manual with the wiring diagram. I haven't needed the manual for some time, either after 13 years of ownership I know how to fix the common faults by heart or I have a reliable 24 year old truck. The question is. Is the light supposed to come on with ignition and go off once the engine is running or is it just a simple switch circuit? Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted April 6, 2013 Share Posted April 6, 2013 On mine there's a relay assembly that lights the brake warning light when the key is in the "engine crank" position to provide a bulb test facility. Quote Link to comment Share on other sites More sharing options...
western Posted April 6, 2013 Share Posted April 6, 2013 same on my 110 to, relay lives in the fusebox behind the metal panel, 3 relays are the same so swap it with one of the others [suggest the start relay, look for white/red trace & plain brown wires] if the engine then doesn't start you need a new relay. or check the black/white trace wires from brake master cylinder cap to the bulkhead connections, one wire on the cap is earth. also if your vehicle has a handbrake on warning light switch, this uses the same warning light as the low brake fluid light, this is a direct connection & doesn't go through any relays. Quote Link to comment Share on other sites More sharing options...
sgnas Posted April 7, 2013 Author Share Posted April 7, 2013 On mine there's a relay assembly that lights the brake warning light when the key is in the "engine crank" position to provide a bulb test facility. After spending some time on it today trying to get it to work like a modern car (comes on in running position, goes off once started) I reread this and think it works as you describe. On only when cranking. I had two faults. Sticky relay ( I only have two and a flasher ) swapped them over and it wouldn't start. "Percussed" the relay on 5 of the 6 sides and it is all fine now Excessive verdigris on the earth wire at the cap end. Had to cut off connector strip and clean up a new section and put a new connector on. Quote Link to comment Share on other sites More sharing options...
western Posted April 7, 2013 Share Posted April 7, 2013 sounds all sorted then, ready for the retest. Quote Link to comment Share on other sites More sharing options...
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