How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mark N Your Own Question
Mark N
Mark N, ASE Certified Technician
Category: Car
Satisfied Customers: 200
Experience:  Saab Master Technician, GM Technician, 30 years experience.
Type Your Car Question Here...
Mark N is online now
A new question is answered every 9 seconds

SAAB: 5 automatic transmission, fuse B,10 A..blown..blow

This answer was rated:

RE: SAAB 1999, 9-5 automatic transmission, fuse B,10 A and fuse 12, 7.5 A blown, what is causing these 2 fuse to blow?

Hello and welcome!


The 2 fuses you're referring to are power supplies to the Transmission Control Unit (TCM). Fuse B is switched power from the ignition switch, and fuse 12 is constant from the battery. Both circuits go directly to the TCM from the fuse box, so the problem is either internal to the TCM, or the wiring harness is pinched somewhere in between.


If you can take the glove box out, the TCM is mounted on the firewall directly in front of it. Unplug it and see if the fuses still blow. If they don't, you'll need a TCM. If they still do blow, there's short in the wiring somewhere. A common place to look is behind the radio. The harness sometimes rubs against the radio mounting box, or the dashboard supports on either side of the box. Look carefully at the harness for damaged wires all around this area.


Hope this helps! If any of this isn't clear, please feel free to write back. Thanks for checking in with us!

Mark N and 6 other Car Specialists are ready to help you

Related Car Questions