My 2000 blazer started 2 weeks ago blowing the ign c fuse 20amp. I replaced the fuse and the service eng. light went off, then 5 days later my service eng. light come back on so I stoped at Auto Zone and retreived my codes they gave me a few codes, P1860 TCC Pulse P0753 Shift Sol A, P0740 TCC Cht, P0440 EVAP Control so I decided to take it into the gargage they decided it was my transmission so they serviced it by changing the transmission fluid and filter but they also suggested I replace the transmission then again this Friday my ingnition fuse 20amp blew again. I have never had any transmission issues and it doesn't drive any different it doesn't see to be shifting hard and there doesn't seem to be a skip that I can hear or feel. I have had my blazer since it was new and have had very few problems with it. Does any one know what my becausing this or does it truly sound as if my transmission is going out. I do have 285,miles on it but I just can't afford a new car right now. Any one's advice would be greatly appreciated.

I'm not sure if this could be related but about a month ago my brake lights were not working and after reading a few blogs I decided to wiggle the flashers and after doing that they came back on and have been working since. Just thought it might be helpful info.

Thanks,
A true blazer lover
Carol

 

if its only when u switch into 4wd i would check the grounds going to the electric transfer case. 2nd gen that is. The 4wd system on the blazer uses the electric transfer case to engage the front axle.
hope it helps
good luck

 

The 20A Ign C fuse powers 2 parts of your ignition switch. 1 part is for start (crank fuse in underhood fuse block ), the other part powers the cluster fuse in the instument panel fuse block which would be your transmission related codes. If you're not blowing either of those fuses I'd guess either you have a wiring problem going into the ignition switch or your ign. switch is failing (my vote). If the transmission was the culprit that cluster fuse would be constantly blowing unless of course someone stuck an oversize fuse in it. (should be 10A)

 

The only fuse that is blowing is the 20 amp ign c fuse that is under the hood and that has happen now twice within the last five days. I went ahead and checked the cluster fuse and as you said it was a 10 amp mine was not blown. I believe I will proceed in replacing the ignition switch.
Thanks for the post.

 

My vote would be on the wiring or the ignition switch. I say wiring because the circuits on the IGN C fuse are not all that high current and the ignition switch would have to be really charred for it to blow a 20A fuse.

For more information about the ignition switch, have a look at this thread:
Anatomy of the Ignition Switch
and let me know how you make out. Reply to that thread if you can with your experience so that it can be added to the article before it is submitted to the Tech Article (DIY) section.