: Renault Scenic 1 - dTi Battery Discharging*FIXED*


TheOne
8th October 2010, 08:42 PM
I have a 1998 Renault Scenic 1.9td and it has suddenly developed a serious problem in that the battery will completely discharge within a couple of hours. I have changed the alternator and the battery this has made no difference. I have also removed the stereo and replaced the relays under the bonnet. This is now driving me mad. there is no visible signs of discharge like interior lights on or boot light or anything like that. The only other sign was that the temperature gage needle would rise and fall with the revs of the engine just like the rev counter and now it no longer works at all. Everything else seems to be working fine. Can anyone help please.

madnoel10
9th October 2010, 10:56 AM
Have you checked if there is a parasitic voltage drain when the car has been switched off and locked - leave it for at least 5 minutes vefire testing.
Also what voltage is the alternator putting out - check at idel and then at around 2,000 rpm.:)

TheOne
9th October 2010, 11:36 AM
Unfortunately have not tested for parasitic voltage drain as yet as I need an amp meter. However I have tested the charging of the alternator with a multimeter at idle voltage is 13.2v and at 2,000rpm voltage is 14.3v. This is a new alternator and battery fitted since the problem came to light. I intend to purchase an amp meter from maplin this afternoon as I suspect parasitic voltage drain is the cause, the lack of circuit diagram does not help either in diagnosing the fault.

madnoel10
9th October 2010, 12:22 PM
Could you not set your multimeter to amps and check between the disconnected postive terminal and the battery? If it more than the multimeter can handle then it must be very high indeed.:)

TheOne
9th October 2010, 04:29 PM
Have now checked parasitic drain it is way to high the meter I got can read up to 20amp the reading is way above this. I have managed to fix the temp gage and doing some diagnostics I have found that if I disconnect the cable leading from the starter to the alternator then the drain subsides to within 200ma. Although disconnecting from the alternator made no difference. I have noticed that the cable from the starter to the alternator has a branch in it, I think that the fault may lye at the termination of this branch where ever this leads to. Oh yes bye the way to answer your question my multimeter can read amps but only in ac mode, very strange I know but there you have it.

madnoel10
9th October 2010, 05:08 PM
Twenty amps is a helluva parasitic drain - sounds more like a short to earth via some heavy consuming component. Even the 200 milliamp drain is probably too high. Although remember you need to let the car sit fully locked for around 5 minutes or to let all electronics power down.:)

TheOne
10th October 2010, 10:32 AM
can any one tell me what this part is and what its function is as this is causing my battery to discharge. It is a small metal box mounted on the bulk head just under the windscreen on the passenger side it has two plugs to it one with three wires and one with six. This box is running very hot almost melting the wires.

madnoel10
10th October 2010, 11:15 AM
Have you checked the glow-plug circuit isn't continuosly live?:)

TheOne
10th October 2010, 08:05 PM
Thank you for your help madnoel10 I have managed to isolate the problem, it turned out that the box is indeed a relay for the glow plugs and that the relay was in fact causing the live to go to ground. Everything is now sorted thank you again for your persistence.

Lagdti
10th October 2010, 08:08 PM
Great news,thanks for the update.:)

madnoel10
11th October 2010, 02:52 PM
Thank you for your help madnoel10 I have managed to isolate the problem, it turned out that the box is indeed a relay for the glow plugs and that the relay was in fact causing the live to go to ground. Everything is now sorted thank you again for your persistence.

In all honesty I have to give some credit to my son who is an electrcial engineer. He realised it had to be a fault going to earth via a circuit that contained a resistance and he chirped in my ear - [B]"Dad could it a fault on the glow-plug circuit - theres a few resistors in that circuit"[ check that out first"/B]

God bless our kids - what would be do without them eh!!:):)