Blowing trunk output?

Hi guys, I installed a Prostart CT-3400 in my wife's Taurus last week. After the install, everything worked fine. The next day, the trunk would not pop. After checking the wiring, resetting the unit, checking the programming I came to the conclusion that the ouput was fried. So I took the unit back to Crappy Tires for an exchange which they did.

Brought the new one home, plugged it in and all is well. The next day guess what. The trunk doesn't work. ?????

Am I doing something wrong here. The Taurus is a 96 without factory keyless but with power windows, door locks, seat, etc. The trunk output is positive so I put in a relay to reverse the polarity and installed a quenching diode. I took the +12 from the trunk switch itself for both pins 85 and 87. 30 is +12 to the trunk and 86 is the - trigger from the module.

Any ideas what could be happening?

Thanks a bunch.

try using a different +12v source. also, if your relay has a diode across 85 and 86, it wont work.

Thanks for the reply.

I thought about trying another +12 source (once I get another module) but I can't see why this would make a difference. Anyone?

BTW, the relay does work with the diode. It just means that it is polarised and the pos/neg have to be on the right side of the anode/cathode.

Thanks for the replies guys.

I'm sure that the trunk is positive. It did work at first but then the remote module seems to blow out its output. That's the part that gets me. I don't understand what would be blowing out the output from the module other than a bad design for the transistor bias. It is rated at 500mA. I checked the relay's coil and it is 83 ohms. So that should be plenty to limit the current draw to less than 200mA. There is no shorts since that would blow the fuse on the +12.

This is the first remote start that I installed but i'm not exactly an electronic "virgin". I did train in electronics even though that was 20 years ago and my day job includes working with PID's and setting PLC controls. Anyway, I'm beginning to suspect a faulty design. This unit is pretty new. From what I understand it was only released in September. Problem is I'm not an "authorized" installer and therefore can't get tech support from them. Maybe there's somethng I'm doing wrong or a simple cause I'm missing it's driving me nuts.

I really appreciate your help.

10nesne1Well, your connection is bacsically correct. Which fuse are you blowing factory fuse or your fuse for the trunk release? If you are blowing the factory fuse than you are hooking it up incorrectly, or if you are blowing your trunk release fuse than you are hooking it correctly when you hit the remote. That's an easy fix because most newer vehicle today the trunk release wire is rested at ground. All the connection you posted is correct. all you need to do is to cut the wire in half and connect the factory trunk relase wire to 87a and the oppsite wire to pin 30 and 12v+ positive goese to pin 87 and 85. Then pin 86 goes to alarm aux output negative.

Relay Configuration:

Pin 87 and 85 to 12+ volt (fused at 15 or 20 amp)
Pin 87a trunk release wire switch side
pin 30 trunk release wire motor side
pin 86 alarm negative output

Good luck

[/QUOTE wrote:

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I'm not blowing any fuses. The negative output from the module goes dead.

The relay setup you describe is the same as I got except I don't go to pin 87a. I take the output to the trunk (30) at the switch which is really the same as 87a and 30 are normally closed.  Here is my relya setup.

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I'm not blowing any fuses. The negative output from the module goes dead.

The relay setup you describe is the same as I got except I don't go to pin 87a. I take the output to the trunk (30) at the switch which is really the same as 87a and 30 are normally closed.  Here is my relya setup.

Ok. Let's try this again.

floaterr wrote:

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This has been kinda touched on but here's my $.02

Find -another- 12v sourse. DO NOT use the one going to the relay.

I'm thinking it's possible that if you installed a diode with the line side on #86 the vehicles keyless entry system is sometime during the night fishing for a ground (for what ever reason). The car removes 12v from the line you connected to and uses the alarm as a ground for something else (accidently). Since the diode is 1amp (more the likely) it is bypassing the windings of the relay and pulling current through the trunk output.

Good luck

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Here is an interesting cause and effect but I'm not quite following your thoughts. If I understand you, the car would turn the +12 off, for example through the battery saver relay, thus making the cathode more negative than the anode. The remote would then go to ground through the trunk output thus pulling too much current through the base and blowing the output transistor in the process. Hum!. Food for thoughts here. Only thing is, the first module didn't have the diode across the coil. i only added it because I thought that the coil field collapsing was the culprit.

Surely my setup is not that different than what many others would do. There are also 100's of Taurus out there so someone else should have seen this problem right?

Is this the wiring setup you're talking about?

I'll be getting a new module on Wednesday and I'm planning on changing the wiring to this.

This way the remote output will be isolated from the trunk circuit.

Thanks JWorm,

The setup you suggest is really the same as I'm picturing above. The diode is already on the relay and it won't hurt anything other than polarise the coil's input. Will it?