555F installation with Viper 555ESP

Hello, I'm currently installing a 550ESP Remote Start Alarm into a 1997 Expedition. This is the first install I've had to use the 555F with and I'm a little confused on one part of the hookup. Basically I'm unsure if the 'Blue (-) Activation Input' requires a pulsed or constant signal from the brain. I have decided to use one of the following:

Harness2/Pin2 - (-) Factory Disarm Output - Pulse Type (Sends negative pulse when remote start is activated)

Harness3/Pin1 - (-) 200mA Status/Factory Re-Arm Output - Constant Type (Sends negative constant as soon as remote start process begins)

I don't see why the 555F unit would need anything more than pulse on activation, as the key is only checked on start-up to my knowledge. I don't have anything hooked up to either at present, so both are availble.

Also, is it absolutly neccesary to use a relay on this circuit? I can't imagine the 555F draws that much current.

Any assistance in this matter is greatly appreciated.

 Regards,

    Matt

Typo in the title. As stated in the actual post, the model of the alarm is a Viper 550ESP; not a non-existant 555ESP.

Thanks again,

   Matt

I believe that it needs to be activated the entire time that the remote start is engaged.  most of the GM's only check for the transponder at first, but I think Ford looks for it all the time.  I tapped the one I did into an Ign 2 (-) output with a relay so that when the alarm powered the Ign 2 circuit, it also powered the 555F.  Good luck.

Excellent, have a slight delay with this because the owner only has 1 key; so waiting for the locksmith to program up another one. But got the module all set. Most likely he will be purchasing the Ford interface kit, as I advised him it's much more reliable than this 555F pellet junk.

Thanks again for the responses!