Date: Sat, 25 Sep 2004 13:41:40 +0100 From: "Gerry Scott" <none> Subject: 9000 Hazard Lights - final instalment
Hope I'm not doing this subject to death, but I needed to give an update on my hazard lights. May help someone else save a bit of money. I've previously posted that cleaning the fuse seemed to fix it. Unfortunately, this fix didn't last. Sometimes the lights worked, sometimes not. Investigated further and lowered the fuse panel to get to the flasher relay unit. When I tapped the flasher unit, the lights would work for a couple of seconds then stop. Did the obvious thing of cleaning the contacts, but made no difference. Still only worked briefly when tapped. Since these units cost a ridiculous £50, thought I had nothing to lose by having a closer look at it (thought there may be a sticky relay or something). The green plastic cover comes off the flasher unit really easily - only three plastic tabs at the end to prise off. The unit consists of a small printed circuit board (pcb) about 4cm by 2cm. Tried it again in the socket and put light pressure on the end of the board with my finger. Hazard lights now kept working as long as I kept a slight pressure on. Obvious conclusion was a dry solder joint. Therefore, thought it might be the contacts under the relays. These are fairly large solder bumps and since I don't have a high tech soldering iron at home, I carefully had a go at melting and re-applying some more solder. Tried again in the car, but still only worked with finger pressure. Then tried the connections from the pins at the bottom of the relay (that plug into the socket). These are soldered onto the bottom edge of the pcb. None of them looked particularly dodgy, but resoldered them all anyway (about 8 connections). Again, these are fairly large solder bumps, so easy to do without shorting anything out. Relay now worked perfectly and reliably without any pressure. Therefore, one of the edge connections must have had a bad connection. I guess these connections take the most strain from bumps and vibrations, since they're the only things which support the relay pcb onto the end connectors. I don't know how well I've described this, but it really is a very simple fix. If you're having hazard light problems, have a go at this fix before buying a new unit. This fix has now been working reliably for about 1.5 weeks. I check the hazards almost every day just to check they're still working. Also passed the MOT re-test with no probs. HTH, Gerry Southampton, UK. '96 9000CSE
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