Stereo Gremlins

[Marigolo]

Hi all, I'm just wondering if someone with more electronics knowledge than me (probably most dmctalk users) could give me pointers as to where to start diagnosing a problem with my stereo.
Behavior is this:

1. Car on + break pedal pressed = Stereo screen dims down
2. Car on + break pedal + Left turn signal = Stereo screen flickers with the turn signal (Happens sometimes only and does not happen with RH turn signal)
3. Car on + reverse + NO hand break = Stereo tells me hand break is on. NO Reverse camera display.
4. Car on + reverse + Hand break ON = Camera feed appears on stereo screen. Too bad I can't go into reverse with the hand break on!

I did this short video where you can see what's happening:
https://vimeo.com/73988581

I think behaviors 1 and 2 are due to the stereo grabbing power from an incorrect cable/power source. Behaviors 3 and 4 are probably some inverted cables and could be fixed by just "swapping" them (?)..
If anyone has an idea as to where to start looking I would love to hear it!
Thanks!!
Mario.

[Patrick C]

It sounds like its time to clean all of your electrical grounds and battery terminals with sandpaper.

http://deloreantech.wikia.com/wiki/Grounds

[Alan]

My best guess for the first two issues (which I think is the same issue) is that there is a connection from the stereo for dimming the display when the lights are on. It's likely hooked up to the brake/turn signal circuit on the left side or the car instead of the running lights. It would be triggered when the brakes or the left turn signal is on and that would cause the screen would dim down.

I'm not sure about the second two issues since I've never hooked up a stereo with a camera or hand-brake warning.

[LordFly]

My best guess for the first two issues (which I think is the same issue) is that there is a connection from the stereo for dimming the display when the lights are on. It's likely hooked up to the brake/turn signal circuit on the left side or the car instead of the running lights. It would be triggered when the brakes or the left turn signal is on and that would cause the screen would dim down.

I'm not sure about the second two issues since I've never hooked up a stereo with a camera or hand-brake warning.

The video helps a lot. And Alan is on the right track. Simply put, the stereo is wired wrong. Whoever installed it got their wires wrong, and it seems they didn't test it either. The dimming when you hit the brakes is definitely a feature. But that wire should go to the headlight circuit, not the brake circuit. The reverse camera and handbrake warning are also just wires that have been hooked up incorrectly.

From the sounds of it, this might not be a project for you to take on yourself. The 4 hour trip to DMC is probably unnecessary. I would recommend just taking it to a local stereo installer and have them correct the problem. But you might want to talk to DMC first and see if you can send them the bill for it when you're done.

[David T]

The stereo you have is very sensitive to the voltage level. If it gets too low it gets weird. You will not fix it till you can get your voltage up higher. May not be possible even by cleaning connections and going directly to the battery. You need a voltage stabilizer for the radio. If it is the OEM radio you may want to consider upgrading to a better one that is more tolerant of varying voltage. Stick a voltage meter on the power input for the radio and see what you get.
David Teitelbaum

[Bitsyncmaster]

It sounds like its time to clean all of your electrical grounds and battery terminals with sandpaper.

http://deloreantech.wikia.com/wiki/Grounds

+1
Sure sounds like a bad ground. Most likely the one behind the relay compartment.

[LordFly]

No offense to either Dave, but I think if you watch the video he posted, you will change your mind pretty quickly. I admit, when I first read it I immediately thought low voltage too. But as soon as I saw the video, it became pretty apparent that the thing is just wired wrong.

[David T]

No offense to either Dave, but I think if you watch the video he posted, you will change your mind pretty quickly. I admit, when I first read it I immediately thought low voltage too. But as soon as I saw the video, it became pretty apparent that the thing is just wired wrong.

I have to admit I didn't watch the video before posting the first time. I still think it is a voltage problem but I did not know it could be wired into the brake warning light! I doubt it is, it is just the voltage messing up. You can try cleaning up connections but I would call DMCH first since they installed it and they should be able to help you. They will know what and how they wired it up.
David Teitelbaum

[Bitsyncmaster]

No offense to either Dave, but I think if you watch the video he posted, you will change your mind pretty quickly. I admit, when I first read it I immediately thought low voltage too. But as soon as I saw the video, it became pretty apparent that the thing is just wired wrong.

Your correct, I did not look at the video. I just did and your correct again. The dimming is to consistant so it does look like they connected the "lights" wire to the brake signal.

[Josh]

Well it is fairly apparent the stereo was wired up incorrectly. I find it amazing how people can screw up stereo installs so bad, it is very straight forward and a very common upgrade for any vehicle.

There is no definitive answer on how to fix the stereo (eg: switch this wire, ground that wire and everything is fixed)

I would start by ripping out all wiring for the rear view camera and starting from scratch. It looks like the reverse light switch trigger is wired to the parking brake.

For the dimming, it is very consistent, it looks like the dimmer is hooked up to the brake switch. I have no idea why someone would do this. Either that or the current load, those old brake bulbs suck up a lot of current and may cause the stereo to dim, especially when the car is off. I had a similar issue with my motorcycle. It has a tired old alternator, so when I hit the brakes the headlight dims.

And finally, check your grounds. The delorean is a fiberglass tub as you know, so chassis grounds are a common problem. I would start by removing the radio and checking the resistance across the ground. It should be in the low single digits. If not, there is a problem. You could also run a new ground to the frame and see if the radio works better.

[Elvis]

Hey cool finally somebody who listened to me and bought the same cool stereo :-)

Yeah that nice guy who installed it didn't test it !!! he swapped two wires. no big deal if
it weren't a Delorean where getting the radio out is a pain in the....


The problem when braking is the very low level of the light input when it detects a high signal.
When high - it should dimm the display.
Problem - the brake lights draw a lot of current which generates a voltage drop. The level it
sees is high enough to detect - lights on.

Solution - put a diode in series to the light sensing wire. Once you have the radio out - which will be soon
as you LOVE the rear view camera when in reverse :-)
PM me if you want.

Till then you can simply turn the dimmer off.

Enjoy the radio, 6548 and I - we love it :-)

[Marigolo]

Thanks for all your suggestions!, I'll make sure I address as many of them as I can!
:wave: