PCM/TCM-bat fuse keeps blowing

[MJames07]

Southwind on a W22 workhorse chassis; 8.1L Vortec engine. Attempted to start the engine and received "no J1850 activity" and "LOW FUEL" messages. Batteries were recharged but no response. The PCM/TCM-bat fuse was blown and it blows a new one immediately. Does not appear to be an critter activity.
Had a new starter installed about a month ago. It started fine until now. I isolated the starter motor but the fuse still blew. I disconnected the TCM and still see the short. Would a failed PCM cause this kind of problem?

Looking for suggestions. Thanks.

[Ultra RV Products]

It's either the TCM or a shorted wire in your harness. It's almost always the TCM that is causing the issue.

[MJames07]

Originally Posted by Ultra RV Products

It's either the TCM or a shorted wire in your harness. It's almost always the TCM that is causing the issue.

Thanks for the response. How do I test the TCM? I can disconnect it again and test with a new fuse. I only tested with a meter and it indicated that the voltage across the fuse slot was 12+ volts. I took that to mean the short was still there. However, when I put the meter in ohms mode and test the side of the fuse slot to ground that goes to the TCM, it shows open, indicating no short.

[Ultra RV Products]

Disconnect the TCM completely and put a new fuse in. If the fuse does not blow, that points to a bad TCM.

[MJames07]

OK. Thanks. It will take a day or so to accomplish. It is fairly difficult to get to the unit.

MJ

[MJames07]

Originally Posted by Ultra RV Products

Disconnect the TCM completely and put a new fuse in. If the fuse does not blow, that points to a bad TCM.

I completed the test as you specified and the fuse did not blow. Therefore, as you suspected, the TCM is bad. I understand that you (Ultra RV Products) provide replacement units. Please send me a contact to follow through with the business transaction. Thanks.