i really hate to ask anyone i dont want to wast peoples time. But i have a 1999 blazer that has ele power probs. First why do i have a hot fuse in the fog light slot in the fuse box and i dont have any fog lights? when i do a scan on the truck it almost always says low voltage and pcm fails all of the self tests.for example it shows. p1875 po153 po756 p1134 p1870 po442 u1042 po751 po742 po146 po154 u1192 po60 u1193 p1810 po155 p1441 po134 po135 p1133 po446 po401 po143 and po440. It runs good,a little rich on the fuel but outher than that. anyone got any ideas?

 

I don't have time to look at my service manual but there is also a relay that controls the fog lights that could be bad.

As for your other error codes, now that you have the list of them, you light clear them and see which of them come back.

 

thank you for responding. i have erased the codes severel times thats what puzzles me. the scam program always says 12.1 volts its to low. thats why ive been checking for any thing that would be draining batt power. Thats when i ran across the fog lamp fuse,its hot and i dont have foglights or a switch. your right i need to trace it and see why the fog is hot..ill get back to you thanks. and thank you for serving.

 

Chasing an electrical drain gremlin can be a nightmare. Good luck, and hopefully we can offer a few tips to help you narrow it down.

If the fog lamp circuit has a fuse without factory fog lamps, there must be another accessory on that same circuit. If you can find the service manual for your year truck you might be able to see what other accessories are on that circuit to test.

If you have a multi-meter that can measure amperage draw and is fuse protected it might help, you could try pulling that hot fuse and with the truck off, put the test leads on the fuse panel posts for that fog lamp fuse to see how much power is being leached. This won't necessarily tell you what the problem is, but it might tell you how much power is being leached, and whether that circuit is the culprit or a red herring.