HO2 problems

[Clay]

Howdy ya’ll
This one is gonna drive me bonkers.
96 explorer 112k 4.0 ohv, 5 speed manual.
I had codes for all 3 o2 sensors and 2 for o2 sensor heaters, so I replaced all 3 o2 sensors, but the heater circuit codes stayed!
Checked the HEGO fuse under the hood, sure enough it was blown, I put a new 15a in it, the codes are still there.
So, after 2-3 days I check the fuse, it isn’t blown, but it isn’t receiving power.
I pulled the fuse, and probed the distribution block for power, no go.
Tried wiggling the wires, no go. Tried wiggling the block, no go.
What would cause only one circuit in the block to not receive power like this?

Topic

[college man]

If the fuse is blowing your either over amping or have a short/ pinched wires.
You may need to plug in one o2 at a time and see if the fuse blows.

[Shaun Flichel]

Ohm out the wires, something in line is shorting out. Look for melted wires near the exhaust manifolds

[Its me]

May want to check the HO2 relay as well.

Karl

[Clay]

Close, but no cigar haha. It came unclipped from the back of the engine and the connector melted on the downpipe.
The fuse problem I found was a bad connection on the underside of the distribution block from the relay to the fuse

[college man]

[quote=”Clayhawk75″ post=168503]Close, but no cigar haha. It came unclipped from the back of the engine and the connector melted on the downpipe.
The fuse problem I found was a bad connection on the underside of the distribution block from the relay to the fuse[/quote]

sounds like you found your problem.

[Clay]

Yup, then a month later I pulled the engine and trans to fix the oil leak from hell. Rear main, intake, timing cover, and oil pan.
I almost wish I would have done it all with the engine and trans stil in the truck, haha putting it back together has been an ass kicker.

[Author]

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