my 97 d1 with 112m miles is a great truck i've had for 20yrs,just repaired rear windows [didn't bypass power found used ecu] over the years i've had to fix cruise control a number of times so quite familiar with system.hoses are all good,diaphram good,changed brake switch,vacuum pump and ecu are left [i guess the engage switch also], my question is can i use a multimeter to add power to pump to see if it lights up? [like a power probe] been awhile since i posted cause bad health diagnosis but all you guys have been helpful in the past and appreciate the imput,thanks again btw, what i mean is if i take my multi meter and put the black wire on battery ground is there a setting on multi meter where i can touch red wire to pump to see if it works [i know there's a battery in unit]

 

I've not seen a multimeter capable of that. But, you could just take a couple lengths of wire and touch them to your battery terminals and the other ends to the pump.

 

i somehow remember someone using there multi meter like that but not sure either and yeah wire's work, found a cheap cc ecu so bought it [guess it never hurts having backup] guess i could use the mm wires!

 

I removed my pump because it didn't work, cleaned it up and oiled the bearings. Used a 12VDC tractor battery to test it with. Lack of use was the problem. I used it for about two weeks and went back to my right foot because it burned way more fuel than it was worth.