Kingwood CRW-3-073, '88 Mercedes 300 SEL

I had this alarm installed a few days ago and the installer said that it was working great except for the car locking. This car has a vaccum lock system. With that in mind the manual said that their was a blue-loop wire in the rear of the main control unit. I looked the installer looked no blue-loop wire. So I went back to the dealer and has them open up 2 more boxes of the alarm to see if I just had a faulty unit. No blue-loop wire in any of them. There are 3 wires that the diagram showed that needed to be connected. The brown negative polarity for the air pump, the RED / blue for the positive polarity for the air pump. Then the main control unit that has to be cut and  and rewired that wire color was GREEN/ blue. The installer said that he connected it correctly and that I was missing a blue wire. Anyone have any knowledge of this situation. The car will arm but will not activate the locks?

I'm considering taking the alarm back and investing in the Viper 791vx

Thanks in advance for any comments.

-Xavier

yea, DEI is a quality alarm and i would highly suggest going name brand on something that has complete control of your vehicle. the mercedes have used vaccum lock/unlock for many years now. there is a diagram on this site to show the proper connection from the regular lock/unlock output to integrate into the vaccum system. here is the link

https://www.the12volt.com/doorlocks/page3.asp#vac

and look at the vaccum lock relay setup. some installers are weary of mercedes because it being german but these are not very difficult to integrate into, other than the fact that you have to sometimes grab the inputs at the pump under the rear seat. good luck and hope this helps.