Weird relay problem

I was transplanting a Best Buy installed remote start.  Since the two cars were almost the same I generally reversed the removal for the install.  The parking lights were working fine for a week (with lock/unlock and after the car started).  Then they quit working.

I checked the wiring diagram on this site on how to use a SPDT relay to convert a negative trigger to + output and this is NOT how they did it.  What they did was they tied together 87 & 86 (black and yellow) and went to +12 with it.  Then 85 was trigger from DEI remote start.  Then 30 was output to parking lights.

This is so different than the diagram, yet it worked. For a week anyway.  I have checked that the relay is getting the power and negative trigger it expects.

I'm very perplexed, help is appreciated.

Brian

Forgot two more points:

Without even checking the wiring I bought a new relay thinking I had fried the 20/30 due to have two 50w fog lights + parking lights on.  New Porter & Brumfeld 30/40 also acts dead, like the first Bosch 20/30.  No click.

If I measure between 85 and 86 (+12 and negative input trigger) I get 0.75 volts.

If I go across chassis ground and 30 (output +12) I get 0.

If I go across 86 and 30 I get 13 volts with engine running.

Chassis ground to negative trigger is 0.56V.

Chassis ground to 86 and 87 is about 13V with engine running.

One clarification on last post.  Ground to negative trigger is 0.56 when relay is NOT plugged in.  Ground to trigger is 13V when relay is plugged in.

I'll stop posting now and wait for some thoughts.... almost sounds like my DEI brain is fried???

profuse-

i understand how relays work.  since i have already confirmed the input+12V is good, and we know the output+12V is not working, i believe the problem lies with the the relay not receiving the negative trigger.  it is the only other relay connection.  that is why i posted voltages between ground and trigger (0.56V) and +12V and trigger (0.75V).

i believe now this is not a relay problem but more likely with the negative trigger.  i would like someone who knows the DEI 551R to comment on the measurements i am seeing.

brian

Thanks Teken, kind of what I was thinking but I wasn't sure whether I should see a full 12V between a powered 12V wire in the harness and the negative trigger.

If anyone knows how easy/hard it is to deal with DEI warranty I'd like to hear.  I don't want to go to an installer, have the unit pulled, sent to DEI.. have them take 2 weeks, send it back.... If they swap units with me so that I'm not without a remote start hat's great, otherwise I'm leaning towards just buying a new brain.

Brian

1995 Cutlass Supreme.

Triplett 2002 (Ohio made, DMM, I've used it for many things works correctly)

No fuse was installed on the parking light wire.

No jumpers moved or programming done.  It was working Sunday evening, then an hour later I went to use it again, nothing.

Nothing disconnected.

Measurement between ground and white wire off DEI brain was -0.58 volts this morning.  (Sorry I missed the - sign in an earlier post, it is negative.)

No way am I parting with my remote start in this cold weather for 2 months.  So I either I buy another brain or I was thinking, does anyone make a relay that only requires a very small voltage to trigger it?  Small, like -0.58 volts? ;-)

Thanks for your suggestions Auex.

auex

so, i went and cut the wire that ought to trigger the relay and as soon as i touch it to ground, lights come on.  then i connected my dmm in series with the wire to measure current.  only 6mA.  i bet this is the problem.  although i have full voltage almost no current coming out of brain.  according to the manual it ought to put out 200mA.

so i looked in the manual, found a 3rd accessory output, also - and 200mA.  connected that to the relay and lights are working again.  of course now they come on as soon as the remote start sequence is triggered instead of after the engine is known to be running but it's better than nothing.  maybe i'll find a new brain on Ebay cheap.

thanks for your help in troubleshooting this!!

brian

My thought kind of mimics auex.  If there's not enough current to trigger a relay, there's not enough to trigger that kind of relay regardless of whether the relay is being used in a "traditional" or polarity reversing role.  If someone knew of a relay that was designed to trigger at much lower currents than "standard" SPDT auto relays I might try that.  Otherwise, it's getting cold, I'm sick of lying on my back under the dash, and using the 3rd aux output more or less takes care of the issue.

Thanks guys, it was a learning experience and I owe both of you a big thank you!

In regards to not enough current to trigger the first relay why would it trigger "booster" relay? Hey it can be true and is. In fact I have seen many scenarios where one didn't work but two did! Not all relays are the same but we hardly see the different wierd ones when we are working with aftermarket stuff. I have worked with all kinds of brand of relays and have found that some will engage the coils with as little as 100ma and others don't budge untill almost 500ma. Most systems are designed to push a relay of about 300ma (a number you've probably seen many times in wiring manuals), however there can be a deterioration of that output over time. And once again I speak from experience. Although somewhat rare you may see a vehicle who's locks or "other" worked fine for a few weeks or even a few months to only find its way back into your shop. The average tech will swap out the unit and all is well. The educated tech will want to investigate and soon they will find that although they still see an output from the unit it seems to be a little short of the mark. So they add an "amplification " relay (the proper term) and Ta Da everything works great again.

So Brian, since you have already changed relays (by the way you don't need to change the wiring, either way is O.K. for this application) the question is did you end up going up in amperage or staying the same? Is your output deteriorated to the point of no return, or can you step down to a lower amperage and get things to work again?

There is one other  thing you might try---a spike diode across the coil. Place a 1 amp diode with the cathode (stripe side) attached to the 12V(+) on your coil contact and the anode (long side) to the negative trigger wire from the unit where it connects to the relay. I know it looks like it doesn't do anything this way but it is correct.  

I can't say for sure why your lights stopped flashing, all indicators say they shouldn't have. The last thing you might do (not to offend) is check your connections. Not just visually. I have techs who tell me "yeah I got 12V going to my line", or "yeah my door wire is connected", but they never put their hands on the lines or pull them off to check physically the contact they believe they have. Most fixes are usually the easy overlooked item so don't give yourself a headache thinking too much into this. Look for the easy stuff. Let logic prevail. 

sometimes dei units fry the terminal coming out of the module, pull the white wire ( pin and all ) out of the module, use a small screwdriver to scrape any residue of the t\module terminal, then take and unplug any of the other wires in that harness that is not being used and remove it and put it in the parking light slot and give that a try.

The current (~6ma) measured with your multimeter while it was in series with alarm output is not the max achievable current of this output.  That was merely what was being drawn at that moment.  Current only draws what is required, so at any given time the measurement is going to give a reading which reflects what the output's connected device is doing......So if you measured this wire open or even through the coil of a relay it is not telling you that 6ma is all it puts out.

I read all posts twice and I have been wondering ...Do you also have Parking lights hooked up to this wire?  If so, do they work?  Also......what is the jumper on the DEI unit set at (-) or (+)?  or is the jumper missing?  (That is what I suspect might be the problem.)

If you have more devices (lights, or relays) hooked up to this wire, you need to isolate them from each other using diodes.

Good Luck

1995 Cutlass Supreme.

DEI 551R, whose parking light output is negative.  Thus the Relay to switch polarity.  Do I "also" have the parking lights hooked up to this?  Parking lights are what the light output is used for.  There is no way to switch the polarity of the output on this model, thus the need for the relay.

Since my last post, the DEI 551R has suffered another internal failure.  The voltage sensing feature has gone awry (please don't tell me i should be using tach sensing anyway, i've been through that discussion).  I had to completely switch off the feature that ensures your car has started because it would start and then shut off 10 seconds later.  I did try the "low voltage sensitivity" setting and that wasn't good enough either.

Impedance: the relay was connected when I measured 6mA.  The relay was verified to work using a simple test wire and 12V source.  The relay would be happy to use much more than 6mA, the 551R is not up to it.

I full expect this brain is going to completely die anytime now.  Lasted about 2 years... not all that great quality.

Thanks.

Just wanted to let everyone know... the voltage sense stopped working not because the 551R was dying, but because my alternator was.  About 3 weeks after the voltage sense feature started shutting down my car after a remote start, the alt went totally dead.

I thought this info would be helpful to some of you installers if you run across something weird.

Brian

No, I'm not interested in being without my remote start in the dead of winter.  Voltage sense is now working, lights work off that extra output..... good enough.

Brian