99 dodge 5.2
I was getting this code
P037
What had happend was during my MagnaFlow install the shop allowed the harness to touch the pipe and melting the the wires. I rewired and still was getting the code (both new o2) checked with my scan tool and live feed was still showing 0 voltage. Rewired and got the same code again.. I found the problem and that was the fuse under the hood was blown for the o2..

I did not have a extra fuse so I took the cigarette lighter fuse from inside the truck and placed it in the o2 fuse slot under the hood. All good now I get voltage to the rear o2..

But wait.. the story of my life.. we have fixed 1 issue and gained 2 more..
Soon as I fired the truck up I get another cell code p1762.. well I am very familiar with this code because I had changed the pressure govonor on sever trucks..
But my transmission has been fine.. shifting perfect.. so I take it for a drive but wait, I don't have headlights.. more on that in a moment. So I am driving with only fog lights and sure enough the transmission is not shifting down to first.. kinda like it stays in 2nd now.. it wasn't doing this before I installed the o2 fuse I assure u.. (the transmission shifts fine going up and back down it just doesn't go into low now when u take off)

So, I clear the code fire it up and in 2 sec it's back. Clear and it's back.. well seems like it's there to stay and I will have to find out what the real issue is because I doubt it is the govonor because the transmission was shifting perfect before the o2 fuse.. (yes I removed the o2 fuse and it still throws the code and does not shift down to first)

OK what the heck... headlights..
I have no damn headlights wtf.. I put all fuses back the way they was.. no headlights.. I check every fuse in the truck and under the hood all good. So I take my noide, light to check if the fuse slot under the hood is working.. first I pull the fog lights fuse and probe it.. bingo I have voltage.. I pull left headlight fuse probe no voltage.. right headlight fuse probe no voltage, (yes headlight switch was on) so I go ahead and check flasher fuse so i turn flashers on probe I have voltage.

So it is apparent I am not getting voltage to the the fuse under the hood for the headlights.. kinda like a bad switch right? But seriously I just drove the truck today and the headlights worked (never had a issue ever) and it suddenly happend soon as I pulled cigarette lighter fuse and placed it in the o2 fuse slot.. so I doubt I have a bad switch..
Is there a fuse I am not aware of for the headlight switch? (Besides the 2 under the hood that are good and are not getting voltage to anyways)

What in the heck possible could be going on????????

 

Strange read several post on the Internet about downstream o2 issue and this tranny code.. nobody followed up so I still have no answer..

I am stating to lean towards bad pcm for the tranny issue but it's the ctm that controls the headlights.. I don't want to spend 500 on both and it not fix the problem. ..

Any ideals from a expert?

 

Found out on another forum that the o2 and the transmission share the same ground..

Disconnected battery, pulled o2 sensor fuse and put back into cigarette lighter location, cut rear o2 wires, turn key to start for 60 sec (reset pcm) , hooked batter back up

The truck now shifts fine and no transmission codes.. So, it is in the wiring I did (kinda doubt it) or the o2 is junk.. as I said it is brand new practicality (bosh) and never has been hooked up since the exhaust install.

Plans: head to the junk yard and pull the wiring harness for the o2.. buy a new O2 (a good one) so I can just have a plug and play with no cutting and wiring crap.


HEADLIGHTS
Well, they still don't work definitely not getting power to the fuse box under the hood for the 2 headlights fuses. I pulled the headlight switch and not sure exactly what I was expecting to see but without knowing what to jumper to see if I have a bad switch I am at a loss..

Anyone have an ideal on how to jumper to see if u have a bad switch?

 

No power to the fuse sockets for the headlight? The power goes through the fuse to the headlight switch, so it won't make any difference at the headlight.

I'd be checking the wiring around the fuse block first.

RwP

 

Lol we must visit the same forums.. unfortunately I don't get online much anymore to help..

OK let me explain.. my fog lights work so I tested the fuse slot in the fuse box under the hood. . If I place my noide light into the fog light fuse slot without the switch turned on there will be no power.. if I turn the fog lights on there will be power and the noide light turns on. Did this to the flasher fuse slot under the hood as well, flashers off no power ,flashers on power.

So, the fuse box under the hood has to be a after the switch fuse box for the lights. Yes, u would think that there will be a fuse before the switch.. the fuse box inside of the truck (open driver door it sits on the side of the dash) there is nothing that says headlights there. (I checked all fuses there and they was good anyways.

Now behind that fuse box that u have to get down on the floor board and look up under the dash to see there are a few more fuses and a breaker.. from what I have read those are not for the headlights as well (I checked the fuse anyways an they are good).

I have read there is 3rd fuse box under the dash by the steering column but I never seen it before and I sure don't see it now..

Would be strange for it not to have a pre switch fuse

 

It is way overdue time for you to pick up the factory service manual. Edit: Which *ahem* is in the sticky at the top of this forum. There's no excuse for flailing around without it. *EndEdit*

Yes, the fuse IS before the headlight.

With a NOID light in place of the fuse, you're just checking for continuity. Which if you had, the headlights would be on.

You need a voltmeter / trouble light that's grounded on one side, and prod with the other side (trouble light would be easier for the go/no-go testing, voltmeter for more precise testing later. Yah, I've got both.)

But yes. The fuse under the hood is BEFORE the switch. It goes, as I said earlier (and maybe elsewhere), Battery --> Fuse --> Switch --> Headlight .

Otherwise, that fuse does almost nothing for safety.

RwP