That's due to poor implementation of a good idea for cost cutting purposes (designing in inadequate relays).
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Hi Paul...
It amazes me that anyone would even consider a single relay...
For the price (to an automaker) of a relay and socket, why in the world wouldn't they use two?
Take care.
Ken
Hi Bill,
I'll try to remember that when they haul away my cold, dead body from the twisted wreckage. ;-)
Cheers, Paul
Yeah - they'll put on your tombstone: "Here lies Paul - but we saved $0.03 on the relay!".
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
The problem isn't the number of relays - one is fine if its contacts are designed for the required current. That would cost less than two of lower current rating *AND* be reliable.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Hi Ken,
I'm sort of surprised as well. I recall the relay controlled the low and high beams as well as the fog lights, so when you turned on the high beams, the fog lights automatically shut-off (no doubt to prevent excessively high current draw and the blinding of oncoming traffic). If it were possible to incorporate a "fail" mode that would still provide at least some light until the engine was turned off, that would have made my trip through the great state of Maine a whole lot more enjoyable.
Cheers. Paul
Hi Bill...
But with one, corroded contacts (at the socket), or an open coil, or dirty/corroded contacts at the switchpoint leave you totally in the dark; whereas two would at least leave one headlamp burning.
Let me tell you (shamed facedly) of what I did when I was young and stupid. (now I'm still stupid, but have elder moments to blame it on :)
Bought one of those 3 in 1 meter kits. Being young and invulnerable I installed it quickly; bundled nicely the 4 wires and oil pressure tube, stuck them through an opening in the firewall, hooked them up, all was good so away I went...
Later that night... on the infamous highway 401, just west of Toronto. Far enough from Toronto that there were no highway lights, but close enough that there was still lots of traffic.
First - thought my foot was on fire. Incredible pain. A few seconds later everything electrical quit. Engine stopped, *all* lights went out. Incredible fear.
Saving grace was only that it was a standard, the starter still worked, so I "drove" myself onto the shoulder with the starter motor.
What I'd done was hooked up the ammeter sloppily, it went to ground, burned a hole in the oil tube (foot on fire), and eventually opened up leaving me invisible, blind, and dead in the water.
Doubt there's anyone else stupid enough to do that, but makes me think a lot about light wiring.
Take care.
Ken
Hi Paul...
Darn! In the last message I admitted to being a victim of elder moments, but you on the other hand have hit the nail right on the head!!!
All that needs to be done is to parallel the relay switched/heavier wire system with the older original system. As long as the relay operates well there'd be virtually no effect, yet if the relay failed for whatever reason, you'd automagically fall back on the OEM stuff.
Fantastic!
Take care.
Ken
Hi Bill,
You may have hit upon the crux of the problem. I had been driving several hours with my high beams on, as the secondary roads through New Brunswick and Maine were completely deserted at the time; perhaps high current draw over an extended period of time contributed to its failure. The relay was located above the front passenger wheel well and I wonder if long term exposure to heat and road grime/road salt could have been contributing factors as well. Then again, Sharon mentioned BOSCH relays were known to have problems during those years, so perhaps I was simply twice blessed. Who knows?
Cheers, Paul
Hi Ken,
That's so typical! The one time in my life f-n brilliant and I completely missed it.
Cheers, Paul
Ahh - yes - redundancy/fail safe. Well - it's all a compromise between cost and functionality. We've touched on 3 philosophies: (1) Marginal (inadequate) relays that are guaranteed to fail on a relatively high number of vehicles in the first 2 to 5 years (the present design philosophy). (2) One relay that is designed with an adequate safety factor to put us way on the high end of the failure bell curve. (3) Two properly designed relays (adequate safety factor) to give the redunadancy that you mentioned.
Perhaps a decent philosophy that an MBA could live with would be use (2) on lower end vehicles (cheapskates), and use (3) on higher end vehicles (SUV's, Democrat elites). :) We probably all agree that (1) is unacceptable for any vehicle.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Hmmm! I like it. However, if you were the corporate lawyer, you might rather the failure disable the lights and cause a reasonable person to pull over and get off the road rather than be tempted to continue driving with a crippled system and possibly start a fire with wiring that engineers and lawyers (and judges and juries) both would agree would be inadequate.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Hi Bill,
I was wondering about this myself, but wouldn't that 99-cent fuse be sufficient to keep all those class-action lawyers at bay?
Cheers, Paul
Hi Bill...
Dang, I've confused apples and oranges again. It's my specialty, and I'm good at it :)
I was thinking more along the lines of those of us (me, for sure) who are going to add relays to our existing cars.
Prior to Paul's revelation, I was going to add relays, driving the coils with the existing headlamp wires. And of course the battery to the relay contacts, and in turn on to the bulbs.
Now, instead, I'm going to simply "steal" the coil supply from the existing wiring, and leave the rest all intact. Then I'll add the rest.
The result (unless this is another senior problem) should be that the voltage drop to the bulbs will virtually disappear while the relays and heavier wiring do their job, but - if the relay fails for whatever reason the lights will continue to operate. Operate exactly as Chrysler designed them, and governments approved them, so perfectly legal. (excepting only whatever additional drop arises from a few mils to pull in the coil, if it still pulls in).
Be interesting to hear Daniel's opinion.
Take care.
Ken
I don't see any problem in doing ti the way you describe it, Ken.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
So relay fails and you want the lights to run directly off of the control wiring with a fuse in it that's guranteed to blow at that point? Not sure I'm following.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Hi Bill,
Sorry, I realize I didn't express myself all that well. What I wanted to say is that the fuse should (hopefully) blow in the event of a serious fault (e.g., overload or electrical short), thereby reducing the likelihood of major damage to the vehicle's electrical system; I didn't mean to imply power be re-routed to the headlights via the control wiring if the relay should fail.
The real question I would like to ask is this: If the relay fails, can we devise a way for the headlights to remain on, at least until the car's ignition is turned off, provided the fuse does not kill power altogether.
Cheers, Paul
Either use your idea of paralleling the control wiring and size it so it can carry the load without burning up, or redundant (parallel) relays. IMO, the K.I.S.S. method would be to use a single name brand relay with contacts rated for 50% (100% preferred) more current than what the real load is - that would give you close to maximum reliability at very small cost increase.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Well, if conditions are such that you CAN use the high-beams, you shouldn't have the fogs on at all because (obviously) there is no fog. If there is oncoming traffic, you shouldn't have the fogs on at all... unfortunately 99.9% of the people on the roads these days turn the
*@#^!ing fogs on every time they turn the headlamps on :-/
Well, when I converted my '66 to relays (and Cibie headlamps) I wired it with a fuese and relay for low beam and a separate fuse and relay for high beam. If the low beams fail, I can at least kick on the highs until I can pull over and either a) swap fuses, b) swap relays, or c) bypass the relay and run direct on the switch (not desirable, but better than darkness!)
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