Using a standard Bosch relay for parking brake bypass

AnthonyO

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Oct 18, 2005
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Don’t roast me. But I bought a Jensen Car710x for my Tacoma. Has anyone ever used a standard relay for the parking brake bypass? I know they make micro bypasses but I have a Bosch relay sitting here. Might as well use it
 

ThxOne

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Don’t roast me. But I bought a Jensen Car710x for my Tacoma. Has anyone ever used a standard relay for the parking brake bypass? I know they make micro bypasses but I have a Bosch relay sitting here. Might as well use it
Does it even need it? Does the parking brake wire on that head unit need to see ground or a hot wire?
 

1aespinoza

Junior Member
May 22, 2013
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Don’t roast me. But I bought a Jensen Car710x for my Tacoma. Has anyone ever used a standard relay for the parking brake bypass? I know they make micro bypasses but I have a Bosch relay sitting here. Might as well use it
From what I understand, the microbypass does a double or triple tap to de-activate the parking brake feature. If you wire it with a toggle switch , it should work.
 

Deiimos

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Apr 27, 2021
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I guess the question is, can you simply ground the parking brake wire and it work? Or does it require a delay or other trick?

First test, if no one has info on that head unit, would be to ground the parking brake wire and see if that works after turning it off / on. Might be that simple. And or then grounding it after power on to see if that makes it work. I did a quick look at the manual and it showed it needed a ground signal, assuming I was looking at the correct manual. :LOL:

I recently made one up with spare parts for an older Pioneer DVD head unit I put in my truck. The Pioneer needed a “delay” on the parking brake wire at boot up, so just a relay won’t work, and I did not want to use a toggle switch to manually do it. I did about 10 seconds after turn on, then the relay kicks on grounding the parking brake wire. I had tons of spare parts from doing electronics repair, so already had crap to play with and make work, but busted out the breadboard and box of old parts to tinker, didn't need any precision timing. Not really worth playing with though if I had to buy parts, I'd just buy the correct bypass module and be done with it. The Pioneer didn't need anything special, I had parts I could make work, so in my case it didn't hurt to experiment, and it is a beat up truck I use to haul crap, so I wasn't about to spend the money on a bypass module if I could get around that. 😅
 
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winkychevelle

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You can likely just ground the parking brake wire. Otherwise just spend the 20bucks on the bypass
 
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AnthonyO

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From what I am reading, grounding it will not work. But using a relay will. It just needs to see a ground after the car is started.
 

Deiimos

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Apr 27, 2021
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If that is the case and it is like the older Pioneer’s, then you need the relay to have a “delayed turn on”. Meaning once the head unit powers on, you need the relay to wait a certain amount of time before it turns itself on, which then sends the ground signal to the parking brake wire. How long the Jensen needs, don't really know until tested I guess, unless you can find someone that has done it for sure.

When I tested my Pioneer, I found that roughly 10 seconds was enough to guarantee it worked every time, so that is what I aimed for when building the bypass.

Only a few seconds after the head unit started was not enough on the Pioneer, it would still give the warning that it would not play video.
 

audiobaun

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Don’t roast me. But I bought a Jensen Car710x for my Tacoma. Has anyone ever used a standard relay for the parking brake bypass? I know they make micro bypasses but I have a Bosch relay sitting here. Might as well use it
No shame in running a Jensen man..Every vehicle has its budget. old Jensen amps are still good stuff to me,Coustic,Realistic,Pyramid and lots others. If it fits the budget and does what you need ?? So be it
 
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Deiimos

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No shame in running a Jensen man..Every vehicle has its budget. old Jensen amps are still good stuff to me,Coustic,Realistic,Pyramid and lots others. If it fits the budget and does what you need ?? So be it
Yeah I've run plenty of budget brands over the years, and I'd like to think most of us are old enough not to roast or worry what brand someone uses.
 

Deiimos

CarAudio.com Regular
Apr 27, 2021
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From what I am reading, grounding it will not work. But using a relay will. It just needs to see a ground after the car is started.
And to add to that, in the event it doesn't need much, or any delay, wire the relay to the head unit remote turn on wire, this way the relay powers on when the head unit turns on, or ever so slightly after. May not be enough of a delay, that remains to be seen, but costs nothing to test. One side of the relay coil goes to ground, the other to the remote wire, then ground the common contact, and connect the normally open contact to the parking brake wire = head unit turns on, relay engages, relay contacts close and parking brake wire gets grounded, will happen pretty fast though. I don't think that will be enough delay, but again, costs nothing to try since you have the relay.
 
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AnthonyO

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Well I ordered a bypass relay from DIY. Says all Jensen CAR models.
 

AnthonyO

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Well shit. Now after I order one I see that the CRUX wiring harness uses the factory pin for ebrake. So I don't even need a bypass relay.
 

Deiimos

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Apr 27, 2021
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I’m not sure what crux means, so can’t really touch on that or what it included. But, my first thought on the factory brake wire is, it will send a signal when the brake is on, but won’t do what a bypass will do, meaning it won’t allow the screen to play video while driving.

I think the first step is to install the stereo loosely (don’t fully snap it into the dash), and see what happens, if you haven’t done that yet, it is hard to say. When I did mine, I wired up my Pioneer on the bench and seen what made the parking brake wire work, and built my relay / delay circuit accordingly.

I don’t believe any factory wiring will have the delay needed. But maybe the crux kit, if it is something special, already included this stuff, I don’t know. I suppose you'll find out once it is installed and you're testing it.
 

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