tach wire, 06 ford f450 tow truck

i have a 06 ford f450 tow truck i need to get the tach wire i went voltage sensing but it has trouble starting up in cold weather dei says grenn white behind emergency brake wire is there but no signal i tested the wire with my volt meter and yes ac tanx

Hey, former towman and current alarm installer here. Do you tow, or is a customer's truck? The wire is actually behind the fusebox, not behind the emergency brake. Unbolt the fuse box (4x 10mm bolts), tug the box out a bit, and you'll see a handful of wires there. The ends of the wires are just capped off with shrink tubing---they are NOT connected to anything. Tach is the light GREEN / WHITE wire. The tach signal on the '05-up Ford Diesels is tricky, and it doesn't sucessfully work with all remote starters----- what brand and model are you installing?

tanx i got it it was a dei a cliford matrix its a costumer i had to change the voltage treshold on the unit

ok guys i posted this a while back i have a lil problem with this tow truck when it sits and it gets cold it doesnt start it goes true its cycle of trying to start 3 time it has a viper5900 in it i tried increasing crank time to 2 seconds and when you start it with the key it does feel a lil bit longer than that any suggestions i reprogramed tach i checked my tach connection