vehicle wiring
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=121274
Printed Date: July 16, 2025 at 8:29 PM
Topic: vehicle wiring
Posted By: howie ll
Subject: vehicle wiring
Date Posted: April 11, 2010 at 2:45 AM
Many people on this site ask for wiring info without testing what we tell you. This is one great reason why you should test what we tell you.
Yesterday I had to install a simple alarm in a Mercedes C class, year 2000. I haven't done one for about 10 years.
I prepped the wiring from here, DirectWire, Bulldog and a UK site. Apart from the trunk release they all gave essentially the same info, loc unlock, black and blue, driver's floor loom, joining just in front of the driver's seat.
Went into trunk, pulled out the trim,got to the pump mechanism and got all the separate doors, trunk and hood triggers, dioded them together, found the trunk release, (one guide stated yellow, the other black, it was yellow), fed the three wires forward to the driver's kick panel and boxed up the rear. I then started to probe for the black and blue wires. I know all the tricks, latch the door lock, push in the door switch, could I find them, well I found a black and two blues, none worked. You've got data from the driver's door, also from the centre console so forget them. I had to strip everything again, pull the back seat squab etc. etc., back to pump and probe there, NOTHING. I carefully stripped the pump motor, after disconnecting the electrics, cut the motor wires joined them to two loops, reassembled , used two mini relays and set it up as, a 5 wire, relay interrupt then ran the wires back to the front. Nearly 2 hours wasted!
This vehicle was a hybrid, using the next gen electrics, the fact that it had a "magic" key should have been my clue.
The moral is don't assume that because someone or a wiring sheet tells you something it's true, TEST it.
Replies:
Posted By: t&t tech
Date Posted: April 11, 2010 at 6:19 AM
You call that simple Howard!  ------------- COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: April 11, 2010 at 8:13 AM
Yes till I realised I had to go pack and dissemble the bloody pump.
Posted By: t&t tech
Date Posted: April 11, 2010 at 12:24 PM
I would have loved to have seen that!
-------------
COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: April 11, 2010 at 4:51 PM
I was sh****g myself, my score so far doing this was 2-1 to the pump at $180 a throw. Reminds me of ER! Actually I just looked it up (after the event of course) on Autodata. The whole bloody system is CAN data switched, not + - voltage so I would have had to use either a non existent can sniffer or do what I did.
Posted By: t&t tech
Date Posted: April 11, 2010 at 4:55 PM
That's why you're the man!  ------------- COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: trevors
Date Posted: April 14, 2010 at 11:26 PM
howie ll wrote:
I was sh****g myself, my score so far doing this was 2-1 to the pump at $180 a throw. Reminds me of ER! Actually I just looked it up (after the event of course) on Autodata. The whole bloody system is CAN data switched, not + - voltage so I would have had to use either a non existent can sniffer or do what I did.
Yeah dude! This CAN thing is really kind of disturbing. Fortunately, although my xB has CAN, it doesn't appear to directly interfere with the alarm contacts -- however, it potentially could. Perhaps that's part of my preference for piggybacking as far as possible off the factory security system (being an amateur) -- automatic integration as it were. Still, my hat's off to a competent professional and that's clearly what you are. Best wishes, Dude :)!
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