We have 2002 chevy trailblazer LTZ, we've replaced the battery twice, new alternator, current draw test comes back normal, reset computer numerious times, pulled all fuses and relays, checked all

Well the first thing to have done is to have the battery tested and make sure the battery cables are free of corrosion and tight. Any auto parts store will test the battery for free.

If you can get it to run, take it to an o'Reilly's or another part house that tests batteries on the car - they do it for free. They can tell you what is wrong.

can i suggest you kill it !!!!!! sorry but there is a draw on the battery ,,,, disconnect each item one at a time till battery dont spark at lugs when you disconnect them ,,, seriousy loossen lug on battery and if no power draw no spark wil be present... maby alittle one cos radio takes a really small current

If the battery is new and ok, and the alternator tests ok, there may be another accessory in the car that is causing the drain. Use an ammeter and one by one pull the fuses out of the fuse box, noting which one causes the drain to go away. There should be no more than .2 Amps draw in a normal vehicle. If it's 2 or 3 amps, this can lead to a drained battery in a day or two.

Check for unwanted current draw. Disconnect the negative battery cable and connect a high impedance test light between the cable and the negative battery terminal. If the light comes on with everything off then something is continuing to draw power. Remove the fuses one at a time until the light goes out. Look at the fuse cover or the owners manual to determine what the last fuse that was removed is used for. Something on that circuit is shorted and needs repaired or replaced.

There appears to be a heavy current draw on the battery, you need to monitor this current draw with an ammeter and then start pulling fuses until the current draw is reduced. This will lead you to the circuit, then you will need to determine the cause in that circuit. This task maybe best for a qualified car electrical technician.

Check all your connections at battery to make sure they are tight, and clean, but my guess is it will probably need to be replaced, unless you have a large current draw happening. Stop in to an Autoparts supplier, or your preferred repair shop and ask them to test your system, as in battery , and ask them to double check that there isn't a large draw when engine is shut off. Sounds like alternator is o.k. as it is charging battery, but battery isn't holding charge, and a quick test by knowledgeable technician will confirm whether it's battery, or something drawing it down. If you happen to have another good battery you can try for a day or 2, that will also tell you.

maybe something shorting out drawing power did u have alt tested before switching out to make sure it was bad- sum auto stores such as auto zone/advanced auto can do a load test on vehicle for free will show if their is an excess draw on elect or if new alt is faulty (does happen) check serpentine belt and pulleys belt may be slipping then check ground strap , starter for draw or some other accessory

You need to check if some accessory is drawing power when the car is not running.
About any inexpensive digital multimeter will have a 10 Amp unswitched range. You would need to detach the negative (ground) cable from the battery and put the meter in series with the leads plugged into it to access that range. - Do NOT turn on anything while so connected! It will fry the meter. Normally, there will be a very small amount of current flowing even with everything 'off.' This is normal as there are things still 'on' even though the car isn't running; the ECU will draw a tiny bit, your radio will too and any kind of clock that keeps time will also draw some current.
If you find anything over 1 ampere, you have a problem which must be found as this will drain any normal battery over a two-day period.
One item may have a failed part and cause this; your alternator. It has semiconductor parts in it (normally 6) called diodes and if one has been slightly damaged, it can draw current from the battery with the engine off and not light the warning light on the dashboard.
Good luck-

make sure the battery termanals are tight,, give it a jump and see, can't hurt.