95-4.6l Posted February 9, 2009 Report Share Posted February 9, 2009 Hi all, When brake pedal is pressed: center high brake light glows brighter (correct), both left and right brake lights *darken* - all four bulbs (incorrect..). I had been getting asymmetrical weirdness before - then changed both bulbs in the center high light which led to current symmetrical but still wrong condition. On changing bulbs i noticed that some of the contacts looked like they'd melted off sidewaysish.. Thought hm, maybe bulbs are still working but have bad contacts and are causing weird flashing. Changed front markers and cornering lamps for kicks. No effect. Should I bother changing front turn signal lights and headlights? Are headlights part of the flashing circuit? The front turn signals have wire type contacts on a plastic blade - which seem more reliable.. Is this a steering column switch problem? Thanks. - 95 deville concours Link to comment Share on other sites More sharing options...
Patrick7997 Posted February 9, 2009 Report Share Posted February 9, 2009 Hi all, When brake pedal is pressed: center high brake light glows brighter (correct), *** Umm, no. Center High Mount Stop Lamp (CHMSL) should be DARK when the brake is not applied, and then should be FULL BRIGHT when brake is applied. both left and right brake lights *darken* - all four bulbs (incorrect..). **** Obviously incorrect. Something is seriously messed up. Those 2-way bulbs only fit in the socket one way, I think, so something is reversed somewhere.... I had been getting asymmetrical weirdness before - then changed both bulbs in the center high light which led to current symmetrical but still wrong condition. On changing bulbs i noticed that some of the contacts looked like they'd melted off sidewaysish.. Thought hm, maybe bulbs are still working but have bad contacts and are causing weird flashing. Changed front markers and cornering lamps for kicks. No effect. **** When you say you changed front markers and cornering lamps, you mean just bulbs, right??? And, those were working properly in the first place, or they weren't?? The melting isn't good either, but I'm not sure it's causing your problem... Should I bother changing front turn signal lights and headlights? **** I'm not sure that's going to help. headlights won't help anything. Are headlights part of the flashing circuit? **** No. The front turn signals have wire type contacts on a plastic blade - which seem more reliable.. Is this a steering column switch problem? Thanks. - 95 deville concours **** I also wonder, do your turn signals work properly?? This is just a brake light issue?? Or the turn signals are backwards too??? I would say it's a bulb socket, but it's doing it on all of them, if I read you correctly.... So that seems highly unlikely. I'm guessing out loud here, but I'd be thinking wrong relay installed somewhere, switch installed backwards somewhere, something along that line. Might be a switch problem, but I'm not sure that switch is in the steering column... If you have a factory service manual, now is the time to delve into that.... I'm also curious, did it ever work correctly??? You just bought this car??? It worked correct for awhile, and now this??? You've had this car forever??? Or, the car got cracked up, and came back from the body shop like this??? I think we need more info. This post probably doesn't help much, but some other very smart people will hopefully chime in. I think more info would really help too. Link to comment Share on other sites More sharing options...
95-4.6l Posted February 13, 2009 Author Report Share Posted February 13, 2009 Hi, thanks for replying. Yes, only changed bulbs in the cornering lamps and the side markers next to them. They were all fine but I had them open and changed them anyway thinking maybe they were somehow bad after many years of operation. No effect. Not really surprised. I've had the car for.. about 4 years. It was fine when i got it. The only possible thing was that after about a year, at times there would be fast flashing when using the directional/turn signals. I only noticed this from inside the car so I don't know what the bulbs were doing. At some point - maybe after i changed some dead bulbs - this asymmetrical flashing would happen where out of the three bulbs in the taillights, either the top two would alternate or the center one would be out asymmetrically from left to right. something like this: brake: XX o x x o o o Then later on, when pressing the brake, assymetrical brightening of the bulbs. Here's what's happening now: lights off + brake pedal: XX x x x x o o lights on + brake pedal: XX o o o o x x ---- lights off + right turn signal: oo o <x> o <x> o o blinks FAST lights on + right turn signal: oo x <x> x <x> X X blinks dim to OFF ---- lights off + left turn signal: oo <x> o <x> o o o blinks FAST lights on + left turn signal: oo <x> x <x> x X X blinks dim to OFF what d'you think? thanks. o - off x - dim on X - bright on <x> - flashing Link to comment Share on other sites More sharing options...
JohnnyG Posted February 16, 2009 Report Share Posted February 16, 2009 Problems like this almost always go back to a bad ground in one of the two sides. I can't really follow your pictographic explanation of the problem, but somebody here will. Generally speaking, go through all the bulb sockets and clean up any corrosion and moisture that is found. Trace each ground wire connection back to a metal ground and ensure that part of the car is grounded too. While doing this inspect for bare wires that can lead to shorts to ground through wires that shouldn't be touching anything. Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
95-4.6l Posted February 17, 2009 Author Report Share Posted February 17, 2009 Problems like this almost always go back to a bad ground in one of the two sides. I can't really follow your pictographic explanation of the problem, but somebody here will. Generally speaking, go through all the bulb sockets and clean up any corrosion and moisture that is found. Trace each ground wire connection back to a metal ground and ensure that part of the car is grounded too. While doing this inspect for bare wires that can lead to shorts to ground through wires that shouldn't be touching anything. thanks for replying Johnny. ah.. will look more carefully at the sockets. sorry for the noob question but, how exactly do i trace the socket ground wire to ground? do they ground to somewhere on the frame or back to the battery negative terminal? when i find out where.. i wire a test light from the socket to the grounding point? - continuity test that wire? sorry for the diagram - couldn't get a monospaced font to stick. basically the top row is the center high mounted brake light then the next three rows are the three bulbs on either taillight. Link to comment Share on other sites More sharing options...
WarrenJ Posted February 17, 2009 Report Share Posted February 17, 2009 Virtually all tail light activity (brake/turn/stop/etc.), believe it or not, travels through your turn signal switch on the steering column. Absent poor grounds at the bulbs, and assuming all the bulbs are good, it's time to look at the turn signal switch. I'll try to find a wiring diagram to send you. Patience, please. Regards, Warren There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
JohnnyG Posted February 18, 2009 Report Share Posted February 18, 2009 What WarrenJ is saying is that all of the 12V feeds to those lights (or groups of lights in certain cases) originate at the turn signal switch. In order to complete the circuits, the bulb sockets (the housings) must be connected to a good ground, usually somewhere in the trunk or near the lenses themselves. If a good ground cannot be found there (by the electric current) it will choose the path of least resistance in order to get a completed circuit. This COULD be back through an adjacent (non-burning) bulb filament and all the way back to the turn signal switch. These stray currents cause all sorts of wierd thing to happen with bulbs, since the current may be enough to light them dimly when they are not supposed to. I think you are seeing evidence of this. Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
95-4.6l Posted April 16, 2009 Author Report Share Posted April 16, 2009 sorry for the delayed reply. it does seem to be the switch on the steering column. it makes a double scritching sound sometimes when signaling a turn instead of the normal single click. now when signaling a turn it will flash 3 or 4 times then completely die - no flashing no light. or it will just not operate. dealer said labor on this would be $350-400 bucks plus part since it's in the steering column. does this sound right? haven't checked costs anywhere else yet. is this the part? http://198.208.187.182/internet/PartImage....cpartnbr=D1518E or does the whole lever need to be replaced? Link to comment Share on other sites More sharing options...
KHE Posted April 16, 2009 Report Share Posted April 16, 2009 The illustration looks like the brake light switch. I think earlier posts refer to the turn signal switch with is inside the column. $300-$400 labor seems steep - even for the stealership... The steering wheel needs to be removed along with the lock plate, canceling cam and then the turn signal switch. The worst part is feeding the wire harness down through the column but that is mich easier if a string is tied to the old switch harness. When the old switch and harness is removed from the column, the string is pulled through the conduit. Then the string is tied to the new switch's harness and used to guid the wiring back down the column. I would think a "pro" at the stealership could complete the job in 2 hours time.... Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
95-4.6l Posted May 11, 2009 Author Report Share Posted May 11, 2009 update.. found a good shop to work on things. it turns out to be a relay - i can't find a picture of it. it looks similar to this: http://info.rockauto.com/getimage/getimage...elco/D1703A.jpg but is square from the top - about 1 inch square by 2 inches tall - and only has three blades on the bottom. numbers on it: 3548813 Z-7356 D 4228 the new one doesn't click as loud as the old one - sounds more like a toyota or something now - quiet.. $65 bucks parts and labor.. phew.. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.