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| dome light https://slantsix.org/forum/viewtopic.php?t=61946 |
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| Author: | emsvitil [ Sun Feb 11, 2018 10:22 pm ] |
| Post subject: | Re: dome light |
Yep, diode to the seat switch power.............. |
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| Author: | '67 Dart 270 [ Mon Feb 12, 2018 8:37 am ] |
| Post subject: | Re: dome light |
Hi Guys, Thank you for taking the time to help with this. The dome light (dimly lit) is on when the door ajar circuit is the only possible source of power. The seat's main power sources, one 10 amp circuit (fuse) and two 20 amp circuits (fused/breaker) are in a switched fuse box (only powered when on ACC or RUN via a relay). When the key is on ACC or RUN the dome light issue resolves. So, if I understand what your saying, the diode would be in each of the door ajar circuit wires. You're suggesting that current can flow back into the dome light? Wouldn't a diode in the dome light (downstream) wire work? Perhaps I don't understand what you're suggesting. Brian |
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| Author: | Pierre [ Mon Feb 12, 2018 10:19 am ] | ||
| Post subject: | Re: dome light | ||
Crude sketch, but illustrates the point. With the diode in place as drawn, path 2 is stopped. If the module has a separate lead to each door switch, then yes you'd need a diode in each.
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| Author: | '67 Dart 270 [ Mon Feb 12, 2018 3:54 pm ] |
| Post subject: | Re: dome light |
Thank you, Pierre. Your explanation and diagram make sense. If I get that far, I'm going to ask about the best diode choice. I had a circuits class back in college, but that was in 1984, and it was once a week from 7pm-10pm, so I was tired a lot. I remember that diodes only let current flow one way but that's about it. Essentially, it would be a diode that will handle a 12v circuit and it needs to be installed so current can only flow into the module. However, I want to check something with you first, maybe the problem is simpler than that; i.e. I may screwed up and caused the problem. There are three other power wires to the module, two of the wires for the module were supposed to be non-switched and one switched. I have all three on switched power. Perhaps there is a switch in the module that grounds the door ajar wires I tapped into (and ran to the module) and completes a circuit, but the module needs non-switched power in order to do so? Put another way, I don't see how power would flow to the module through those door ajar tap wires when the door is open if the wires to the module are tapped into the door ajar circuit ahead of the ground (door switch). Wouldn't the current simply run to the shortest path, the door switch, and bypass the branch to the module? Maybe I better make those two module power wires unswitched first and see if that fixes the problem. Feel free to give me a big "well, yeah, first you have to hook it up right, Brian." Brian |
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| Author: | Pierre [ Mon Feb 12, 2018 5:01 pm ] |
| Post subject: | Re: dome light |
I don't know how the module functions internally so I can't 100% answer what the outcome of switched vs un-switched leads would do. You are quite correct though, you need to get it wired as intended before evaluating function. Who knows what it's doing inside. Unless you have internal module schematics.... Disconnect these leads and run some temporary jumpers directly to the battery to figure it out so you don't have to run wires and make it pretty unless necessary. The diode, if necessary, doesn't need to be anything fancy. Any labeled silicon general purpose will be fine. You just have to watch out for the current rating. We don't know the exact function of the wire so we can only guess at the current. What gauge is the oem wire in question? You can parallel a bunch for safety margin. You are correct with the one way valve - however it is at the cost of dropping voltage, typically 0.4-0.7 volts. |
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| Author: | Charrlie_S [ Mon Feb 12, 2018 5:38 pm ] |
| Post subject: | Re: dome light |
I haven't looked at the wiring diagram for the seat module, but doesn't it use the door switch to "tell" the module to unlock the seat belt, when the door is open? If that is the case the module is "seeing" the ground through the bulb. Similar to a cruise control module needing to see ground through the brake bulbs, to be engaged. |
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| Author: | SlantSixDan [ Mon Feb 12, 2018 6:35 pm ] |
| Post subject: | Re: dome light |
Charrlie_S hit on a point I was going to bring up: make sure not to disrupt any safety-related function of the brain box. You'd hate to have a crash where the first thing that happens is the battery is obliterated, killing power to the car (and brain box), and milliseconds later whatever electric lock function of the seatbelts might exist fails to operate because of a wiring change that didn't seem related. Or it might not even take a crash; just make sure your added diodes don't screw up some function of the brain box that needs to work for the seatbelts and seatback latches to do their safety-related job correctly. I don't have the answer, but do your homework. |
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| Author: | Pierre [ Mon Feb 12, 2018 7:27 pm ] |
| Post subject: | Re: dome light |
Ok, I found the corvair link in the other thread that details all this. Quoting from it: Quote: When the operator opens the door, the door ajar switch completes a path to ground on circuit G75 for the driver's door, and G74 for the passenger's door. The seatbelt control timer module then supplies voltage to the solenoids located in the seats, unlocking the seat belts.
This is just a signal ground. Go to radioshack and get you a 1n4001 and test with it (the stripe on the diode's body should be facing towards the switch). If it breaks anything else (run through the very specific tests he lists), either get a door switch with multiple independent contacts or just add another switch. Again though, correcting the power wiring needs to be done first - the article talks about different things that happen on changing the key position so it does indeed matter.This system has a timer control module - you installed that, yes? Do me a favor to sate curiosity - before correcting the wiring - and with the key in whichever position makes the dome light dim - unhook both leads to the door switches - put positive lead of volt meter to one lead and negative to ground and let me know what the voltage, if any is? |
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| Author: | emsvitil [ Mon Feb 12, 2018 7:37 pm ] |
| Post subject: | Re: dome light |
Wait a minute. If the door opens, the seatbelt unlocks. I don't like that feature. I would only want the seatbelt to unlock if I push the button. |
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| Author: | Pierre [ Mon Feb 12, 2018 7:56 pm ] |
| Post subject: | Re: dome light |
Quote: Wait a minute.
It's the way chrysler intended it to work apparently. Why would you want the belt locked (not in the buckle, but locked as in won't allow additional slack) with the door open anyway? If a crash forced the door open the g-sensor in the unit should kick in.If the door opens, the seatbelt unlocks. I don't like that feature. I would only want the seatbelt to unlock if I push the button. Random thought - what's going to happen if you force the dome light on via the headlight switch? That's just the same as opening the door to complete the ground. |
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| Author: | emsvitil [ Mon Feb 12, 2018 8:02 pm ] |
| Post subject: | Re: dome light |
I now think you're talking reel mechanism being locked/unlocked. I was thinking the latch would unlock. Reel mechanism makes more sense. Is there a time delay? What happens if door unlocks in a wreck? |
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| Author: | Pierre [ Mon Feb 12, 2018 8:12 pm ] |
| Post subject: | Re: dome light |
Yes sorry I should have made it clear - that quote referred to the belt retraction mechanism, not the buckle. The solenoids its talking about are what clamp down on the belt. As mentioned - it has an accelerometer (g sensor) in it to take care of crash scenarios. |
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| Author: | '67 Dart 270 [ Mon Feb 12, 2018 9:06 pm ] |
| Post subject: | Re: dome light |
All well taken, thanks guys. Yes, I believe that I should first change those two circuits to unswitched to see if that takes care of the issue. The seats/belts seem to be working properly when the key is in ACC or RUN position, but the reel isn't releasing when the door is open and the key is off like it's supposed to. That's what I was asking about...the wires that I spliced into the door ajar wires are ahead of the door switch. Unless they have their own ground, I don't think current would flow through them. My assumption is that those unswitched wires are that way for a reason....not just to power the reel release, but also the perhaps there's an internal switch in the module so those wires I tapped from the door ajar get a ground. Brian |
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| Author: | Pierre [ Mon Feb 12, 2018 9:57 pm ] |
| Post subject: | Re: dome light |
Brian I'm not sure what you mean by "ahead of the switch". The wires start at the module. The module has it's own ground wire. By this nature since we don't know what happens in the box exactly then the wires have the possibility to be at ground in some fashion. Also, remember it doesn't have to necessarily be at ground. Say the module has parts of it that run on 5v, and 5v is present on the wire (this is precisely why I asked you to measure .....). You now have 12v on one end of the led and 5v on the other - there will still be current flow. Current will flow from high to low, even if low isn't zero (ground). |
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| Author: | '67 Dart 270 [ Tue Feb 13, 2018 7:40 am ] |
| Post subject: | Re: dome light |
Thanks Pierre, right, the module actually had 6 ground wires, and yes, it might also have less voltage differential flow paths (it has at least one current flow path that makes the dome light dimly lit). I'll wire it correctly and report back if there is still an issue. Dan's point about putting diodes in the circuits is well taken, safety first. Brian |
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