Ionstorm66 Posted October 4, 2020 Share Posted October 4, 2020 So I have an issue with my accessory circuit is floating. It causes my dash cam and radio to power on. From what I've seen it is fed from the key switch, but nothing grounds it with key off? Maybe the stock radio had enough draw to pull it down? If I put wipers on full blast, it pulls down the circuit. I think I am going to just install relays inline with the accessory and ignition, and short them to ground on the NC. Quote Link to comment Share on other sites More sharing options...
Step-a-toe Posted October 5, 2020 Share Posted October 5, 2020 Anyone understand ? Does your query need rewriting? Do you now run non standard, new radio? Quote Link to comment Share on other sites More sharing options...
Ionstorm66 Posted October 5, 2020 Author Share Posted October 5, 2020 3 minutes ago, Step-a-toe said: Anyone understand ? Does your query need rewriting? Do you now run non standard, new radio? Floating means its not hooked to 12v or ground. It is picking up noise from other sources. My radio and dash cam pull power from the B+ circuit, and are switched on by the accessory circuit. This is pretty standard, and is how the factory radio worked. The issue I have is because the line is floating, my new electronics are getting triggered by the noise on the line. The wipers are on the same circuit, so turning them on pulls the circuit low. 1 Quote Link to comment Share on other sites More sharing options...
ferp420 Posted October 5, 2020 Share Posted October 5, 2020 Is the radio buzzing or is it browning out from lack of power Quote Link to comment Share on other sites More sharing options...
Rampage Posted October 5, 2020 Share Posted October 5, 2020 Does voltage return when you turn the wipers off? If it stays at 0v then the relay would work. If the voltage reappears then you should find the source of it. You said "inline", so are you going to cut the IGN SW "ACC wire" and wire the relay Common to the ACC circuit and the NO to IGN SW ACC and the NC to ground? One side of the coil to ground and the other to IGN ACC. And the same with IGN? Those relays would have to be high amperage contacts. I think it might be better to do the same with a relay, but only to power and then ground the radio and dash cam wires. Quote Link to comment Share on other sites More sharing options...
Step-a-toe Posted October 5, 2020 Share Posted October 5, 2020 And would you use diode protected relays to prevent any weird feedback? Thanks for expanding on your original query Quote Link to comment Share on other sites More sharing options...
Ionstorm66 Posted October 5, 2020 Author Share Posted October 5, 2020 4 minutes ago, Rampage said: Does voltage return when you turn the wipers off? If it stays at 0v then the relay would work. If the voltage reappears then you should find the source of it. You said "inline", so are you going to cut the IGN SW "ACC wire" and wire the relay Common to the ACC circuit and the NO to IGN SW ACC and the NC to ground? One side of the coil to ground and the other to IGN ACC. And the same with IGN? Those relays would have to be high amperage contacts. I think it might be better to do the same with a relay, but only to power and then ground the radio and dash cam wires. I cut both sides of the ignition switch harness on my donor car. They don't have to be that large of relays. The B+ feed to the ignition switch is only the 1.25/16AWG fusible link. I replaced mine with a 80A fuse, they fit right in the fusible link holder. So you would only need an >80A relay. Quote Link to comment Share on other sites More sharing options...
DaveT Posted October 5, 2020 Share Posted October 5, 2020 No power feed is grounded when the key is off. When power is switched off, the circuit is left open. The loads inherently pull the voltage down, since there is no supply. The wipers should not significantly effect the voltage on the power feed to them. The 12V has to be solid enough to power them. The stock radio is nothing fancy. Probably only drew an amp or 2 cranked up. There are 2 power feeds to the radio - one is switched, the other is always on, to keep the memorized stations from being cleared. Quote Link to comment Share on other sites More sharing options...
Ionstorm66 Posted October 5, 2020 Author Share Posted October 5, 2020 3 minutes ago, DaveT said: No power feed is grounded when the key is off. When power is switched off, the circuit is left open. The loads inherently pull the voltage down, since there is no supply. The wipers should not significantly effect the voltage on the power feed to them. The 12V has to be solid enough to power them. The stock radio is nothing fancy. Probably only drew an amp or 2 cranked up. There are 2 power feeds to the radio - one is switched, the other is always on, to keep the memorized stations from being cleared. Im not having issues with the key on, its when the key is OFF. The wipers on high are a direct connection to the wiper motor, and thus a very low resistance path the ground. This keeps the ACC line grounded with the key off. With out that draw, the ACC line is floating, and pulls up and triggers my radio and dashcam to turn on. Flipping the wipers back on turns them off, as it pulls ACC back to ground. I guess I could just install a dumby light or resistor to pull it down. Quote Link to comment Share on other sites More sharing options...
DaveT Posted October 5, 2020 Share Posted October 5, 2020 This is very weird. Makes no sense. Are the cam and the non-stock radio powered by that line, or is it just some kind of sense input for them? What are they powered by? Quote Link to comment Share on other sites More sharing options...
Ionstorm66 Posted October 5, 2020 Author Share Posted October 5, 2020 19 minutes ago, DaveT said: This is very weird. Makes no sense. Are the cam and the non-stock radio powered by that line, or is it just some kind of sense input for them? What are they powered by? The radio and cam take the main power from the B+, and are switched on by the ACC. The stock radio was the same. Quote Link to comment Share on other sites More sharing options...
Rampage Posted October 5, 2020 Share Posted October 5, 2020 Does any voltage show up on the ACC wires when you turn the wipers off? 1 Quote Link to comment Share on other sites More sharing options...
DaveT Posted October 5, 2020 Share Posted October 5, 2020 Hmmm... the stock radios in mine the power was switched by the key. Only the memory feed wire stayed on. What model and year car are we talking about here? Quote Link to comment Share on other sites More sharing options...
Ionstorm66 Posted October 5, 2020 Author Share Posted October 5, 2020 28 minutes ago, DaveT said: Hmmm... the stock radios in mine the power was switched by the key. Only the memory feed wire stayed on. What model and year car are we talking about here? If you check the draw, it actual draws more power from the B+ than ACC. Atleast my 92 AM/FM/Tape did. Quote Link to comment Share on other sites More sharing options...
Step-a-toe Posted October 5, 2020 Share Posted October 5, 2020 When I have weird electrical things going on I use those blue or black enclosed diodes you find in the EA81 and EA82 wiring looms. One problem was sending me nuts, until about #5 diode was added to my additional wiring and components Quote Link to comment Share on other sites More sharing options...
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