central locking, 2004 pt cruiser

hi i'm new here and i'm working on relay right now and i have following question about relays..

how can u put a relay on this system and what is the use of resistor?

lock/arm requires a negative trigger thru a 3k ohm resistor. Unlock/disarm requires a negative trigger thru a 7.2k ohms resistor. Unlock require double pulse. Must use relay ~br~ ~br~ Also found at the keyless entry module located above radio in the center of the dash.

where will be the negative wire of door lock will tap on the 86?

Does the relay should always a constant power when using it on car?

Does your alarm have a 2 wire or a 6 wire lock output?.  If 2  set to neg. output which should be the default,  take the lock wire to 85 on the relay. 86 is a permanent 12V+, 87 to a good ground, and 30 via the 3k resistor to the control wire. Take unlock to  85, 12v+ to 86 and again a good ground to 87. Output from 30 via the 7.2k resistor, join both these wires to the factory lock/unlock wire. It's position and colour should be available on the forum database. If your alarm has 6 wires use the installation manual to set it for negative locking then place the resistors on your lock and unlock wires and join as above. 2  things, I've only ever done a Voyager and the resistance values were much lower than you've given but I  might be wrong and secondly you can measure the different values by removing the switch and measuring across each (lock and unlock) contact.