'92 T.D.iC Glow Plugs won't switch OFF !

[Doctor Who ?]

Hello and Good Afternoon to everyone in my Computer. I have a little problem with my '92 940 T.D iC .... Hmmm. The blooming' Glow Plugs wont "Power Down". The Relay, I can "Manually" switch off by disconnecting the "Earth Wire", so that's not stuck (?) My Temperature Gauge works ok ... I've found, another what looks like a "Temperature sensor" behind the "Alternator bracket" and established a reading of 1.9 ohms Engine warm, and an Earth and a 7 Volt feed to it (Gray plug, two wires).These wires have no "Colour
collaboration (?) with any on the Square plug at the Glow plug Relay
IS THERE any other "Device" that I could check (ie Timer.. is'nt that in the Glow Plug Relay ?) before I start getting the "Matches out" please ?

THANKS TO EVERYONE

[Peter Milnes]

What exactly is the problem? Is it just the warning light staying on or is there power to the glow plugs constantly? If you wish to stop the power reaching the glow plugs (as a temporary measure) remove the 80Amp strip fuse which is screwed to the underside of the relay. If the relay has been off for checking and has been replaced with the red wires to the strip fuse the wrong way round (quite common when not quite realising how the circuit operates) then you will only have to swap the wires to their correct position to restore normality. However if the internal relay contacts have become welded stuck you will need a new relay. Personally I think the relay needs replacing. Don't throw away the old one as it can be repaired fairly easily.

All the best, Peter.

[Doctor Who ?]

Hi Peter ... Thanks for that ... Yes, a bit of a puzzler at first was this to me,
I've "Spannered" since I was big enough to use One. The problem started as they do, a "While back" (the Car doesnt get a lot of use) 5K in nearly 2 and1/2 Years (!) The Glow Plug Relay (inner Wing o/s near the Battery) started to"Chatter" (?) when you (or I, or anyone, probably) first started up, I used to "Get round it" by simply switching off and re-starting again ..... To cut a long story short I was "Out" in the Car and it did the famous "Fail to proceed" Turn the "Key", Dead, (as the parrot) no crank, its done this too a few times a "While back" (and more recently). Back at "Home camp" found Battery voltage down to, ah "Less than 12volts" Boost start normal .. but couldn't get charging voltage up to anything like 14volts sooo, I went out and purchased a very nice new, from Volvo, 960 spec' Battery (the other one had done about Six Summers..... Assumptions can get expensive ... though because further checking found as per my first post. Yes, the "Glow Light" was working normally, always has. Much Oil post Midnight has been burnt (togther with those other "Spirits....") and yes it would seem, a new Relay purchaced again from the Dealers, don't worry it runs in the Family, has solved that little "Glitch".....

Please tell me though ... Repair ?

How does it come "Apart", looks as it should (?) "Anti tamper construction"

[Peter Milnes]

Surprisingly easy, once you run around the seam removing the small amount of silicon sealant. With the silicon out of the way you should be able to prise the lid clear of the innards and then closely inspect the workings. Often the fault has been due to the contacts getting worn and possibly not in synch. There are two contacts wired in parallel, but if only one makes proper contact that takes twice the current and gets burnt. The cure for this is to thoroughly clean the contacts and adjust them so that they both contact the fixed contact at the same time (small amount of judicious bending). You will then have a good spare for when it happens again (hopefully some time in the distant future).

All the best, Peter.