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Help reading wiring diagram? Stumped on Battery Drain
I have downloaded the FSM online and have looked at the wiring diagrams. It's not clear to me what I'm looking at because what I see in the wiring diagram is not what I see in the car, though I have to say these wiring/connector/harness diagrams confuse me.
We're trying to solve a battery drain problem. The car is drawing 700ma just sitting there with nothing on. But I also think I saw 300ma once.
My son removed the dash to paint it and we've put it all back in, as well as adding a new radio....all at the same time. I suppose that doesn't help matters - doing too much at once.
The battery drain stops when we pull the 7.5A Room fuse. I do see on the white 3-pin radio connector (with switched power), that the red wire with black stripe has a short to ground. I can't find in the wiring diagram what this actually runs, but it appears to go to the amp under the glove box. I looked in that connector and there is no red wire with black stripe. We will be removing that amp as we are not using it.
According to the wiring harness kit he got from Crutchfield, this wire is the 'illumination' wire. I don't see in the wiring diagram if that is correct or not.
Any idea if this wire should be shorted to ground? Any idea where it goes to?
i asked because you said the majority of the draw is from the room fuse and afaik none of the radio wiring is tied to it, well except perhaps dimmable lights like the ash tray light and the radio dimmer. the room fuse is mainly for interior lighting so i'd focus on eliminating all possibilities in that respect.
unplug the radio, unplug the glove box light, check draw.
Last edited by RotaryEvolution; 07-12-15 at 02:13 PM.
OK. I guess that makes sense, but it blows my whole idea of what was wrong out of the water.
Back to square 1.
The glovebox light was not on, it does not come on whether the glovebox door is open or not. With the bulb removed, both + and - sides of the socket are shorted to ground.
We connected the ammeter up again and see 700 ma with everything off and the doors open. When the passenger door is closed, the current immediately goes down to 340ma. Closing the driver's door does nothing.
I have a feeling this is going to be difficult to troubleshoot.
actually it should be easy. you know the circuit, and you know that opening and closing the passenger door does something, so really you'd need to start at the door switch.
The dome lights were working for the passenger door, but the driver door switch is intermittent - but that should not be related....unless it was grounding out?
Anyway, I don't like 'fixes' like this because without finding the cause, I wonder if the problem will just come back at anytime.
Thanks for the suggestions -
Now.... on to the next problem - which I already have found.
My son put LED lights in the instrument panel/cluster. I know that they can be put in 180 degrees off and have the + and - switched around. We wanted to test this before screwing the instrument panel in. But, none of the dash/instrument lights are working.
The only connector I have connected to the black bezel thingy with the blinker switch, cruise control, etc...is the light switch connector.
To test this, I connected the light switch, which is working as it's making the lights pop-up and turn on. None of the instrument lights are lit, no matter how I rotate the dimmer switch.
My son said when he bought the car that the instrument lights did not come on.
make sure the parking lights are working, that is another failure mode of the headlight switch is in that you can lose the parking light activation circuit which also powers the dash lights.
The LED lights he bought can be put in either direction and they work. That's good news. The shift up and high beam lights work when the key is turned to the on position. When the bulb is removed from either of those 2 lights, one side is shorted to ground, the other one open. There is 12V on one side, 0 on the other when the key is in the on position. This makes sense and should be the proper way they work.
The other lights in the dash don't work the same way. Both sides are shorted to ground. There is 0V on both sides when the light switch is on. This also makes sense for the 'illumination' wire on the radio. It's acting the same way, shorted to ground. This should not be and has to be all related to the same issue.
Additionally, the parking brake lights do not work. For some reason, the previous owner cut the parking light wires at the taillights and spliced in some other wire for who knows what reason.
I'll connect those wires back together at the taillights and see if that makes any difference.
Lyger...I'll check the front parking lights to see if they are working though to see if your theory is the problem.
Got the switch out. Found the link HERE to fix the switch, but there are no pictures anymore. Need to find those pictures. Or maybe buy a different switch somewhere?
mostly it's just replacing the relays on the board and cleaning the burned wire connectors. or you can replace it with a used unit, or buy a rebuilt one. been a long time since i saw the repair writeup for it.
cant give a suggestion on how to easily test it, i just install it in my car as i know the lights themself work. marks DIY for the repair is probably long gone sadly, its been about 10 years since he put the DIY up. iirc there was a seller on ebay who sold rebuilt switches. i may have a used one but i haven't gotten around to testing them and listing them.
http://www.ebay.com/itm/Remanufactured-1986-1991-Mazda-RX-7-Headlight-Switch-/251713719741?hash=item3a9b4e8dbd&vxp=mtr
keep in mind you get $40 back if you send in a core.
however i dont know why he has all years with the same part, S4 and S5 work differently and are wired differently. no plug and play swappable.
Last edited by RotaryEvolution; 07-12-15 at 04:04 PM.
After thinking about this further, I don't think that our problem is the light switch.
The reason: The light switch is currently out of the car. I went back to the dash/instrument panel and checked both sides of the gauge lights. Both sides are still shorted to ground. I don't think that this it should be this way. It seems like we have a wire shorted to ground somewhere that isn't supposed to be.
With the light switch out, it can't be the cause of the shorting on both + and - sides of the dash light bulbs.
The previous owner messed with the taillights so that's where we're starting to investigate. I did see a splice with some green electrical tape around it. I took the tape off and found that all the wires connected together here are green with a green stripe. I'm guessing all green wires/green stripe should be ground?
I wish I could understand those connector/wire/harness diagrams better.
We have the front side blinkers disconnected, all the tail/turn/brake/reverse bulbs out and short connectors disconnected. The instrument panel is out (round black and white connectors), the headlight switch, blinker, etc. connectors are disconnected. We have the OEM amp on the passenger side removed, the theft module is not installed and we still get a short to ground on the illumination wire on the radio, as well as the supply wires to all the items listed above.
I'm afraid I don't know how to troubleshoot this type of thing.
i think you're going about it the wrong way. you will get resistance to ground on the power circuit of most circuits. what i would do is make a jumper to the battery with a 15a fuse and apply power to one of the sockets + terminal and see whether the fuse or the lights light up.
that'll at least rule out a pinched wire grounding issue.
the light switches on these cars are hot garbage, i have 7 in the shop, at least 6 of them have a faulty park lamp circuit(meaning i may have one good one left but i'd have to install it into my car to test it. bench testing is inaccurate, they have to physically load a circuit to fail an amp draw test). basically speaking, i wouldn't be too surprised if it is simply just the headlight switch that's causing it.
the other thing you can do is tap a 12v power wire into the parking light circuit at the switch itself. also look at both ends of the connector to the headlight switch and the harness side. if any pins look cooked, yup. you found it, even if non look crispy, still doesn't rule out the switch.
Last edited by RotaryEvolution; 07-12-15 at 06:01 PM.
. I guess if you put the probe in the fusebox in the room fuse slot, then listen for a tone and when it stops, that's where the short is? But, I guess you need to know the route of the wiring also.
Has anyone used one of these to look for shorts in wiring?
I wish I could understand those connector/wire/harness diagrams better.
you didn't mention what year the car is, but if its an S4 Mazda changed the diagram style and the 88 manual is easier to read, imo.
i find Mazda diagrams really easy, power comes in from the top, and ground is at the bottom. the only tricky part, is that they don't really organize the powers by fuse number, only by function (b+, acc, on, start)
failing that there is a very over detailed "how to use this manual" section in the front of the diagram
I wrote a simple how to on how to fix the headlight switch. A trace on the circuit board cooks because it is too small to carry current for the parking lights and the dash lights. You need to also do the headlight relay mod along with repairing the circuit board within the switch. Both are in the link below.
We did get that probe tester thingy today. It came with a video explaining how it works. The video gives a demo on a nicely wired board with lots of space between the wires. This makes it easy to show how the tester works in theory, but in practice I think it's a little harder when trying to follow wire bundles you can't see around corners.
Anyway - here's what we have now. The instrument cluster is removed (round white and black connector are disconnected) The Room fuse CIRCUIT still seems to be the trouble since we don't get any dash lights to light up. And, both sides of the dash light traces on the PCB are shorted to ground. Obviously, one side should be, since it's the ground. The other side should be open to ground since it's getting the 12v to light the bulbs.
With the tester, it tells you very obviously if you have a short or open. What we've done is remove the room fuse, put the tone generator probe in the wiring side (not the 12v side) and shut off all the interior lights (switches in the all off position) and the tester says there's an open. That's good. Once we turn on a map light, it switches to tell us there's a short. If we turn the dome light on, it goes to short. If we put the dome light switch in the middle and open a door, it goes to short. The whole time, the rear tail/brake, etc light connectors are connected and there are bulbs in all the sockets. Would this mean that the body/lighting wiring is OK?
That got me thinking about the taillights that don't come on. So, with the room fuse out first, then inserted, I took 12v battery voltage and injected it into each of the taillight connectors and all the rear lights work OK, with no fuses blowing, no sparks and no fires.
When I measure resistance from the Red/Green wire (Illumination) on the round white connector to ground, there's a short. I don't think this should be. Would this mean that the wiring to the instrument cluster is what is really suspect? The Illumination portion of the wiring (including radio, since that's also shorted)?
I'm wondering if it is the light switch that might be bad...or at least the dimmer portion of the switch? A way to test the light switch would be nice.
07-12-15, 01:46 PM
