Belinda the Beluga Whale 1990 Chev r3500 build

[SuperBuickGuy]

and winning
I'm working on the truck and trying to figure out why the powered side of the relay has 12v

the ONLY way that's possible is if the oil pressure switch is stuck on... or

shall we see if ####ery has occured?
solid yep

but that isn't the issue... I heard the sound of a short above
well what do we have here?

yep, full ####ery


my guess is the PO replaced the a/c pump and didn't make sure the wires were clear when he tightened the brackets back on.... then thought the pressure switch wiring was bad....

I do not have many nice words to add so I'll just stop here.

[Dan Barlow]

Welding the frame back together.......yeah , that'd be a good idea .

[SuperBuickGuy]

We think it's the firewall plug... haven't taken it apart yet but the truck is far close to component pieces now
after, of course, taking the column apart

if someone is looking for the HOT controller - it's right there right behind the steering brace

tomorrow or whenever's issue

also pulling the bed back off to weld the frame back together

[SuperBuickGuy]

The tan/wht wire is a signal for the ECM to know the pump is being powered, e.g. the bearer of bad news if it's hot w/ the engine off, not the cause of it. The dk grn/wht is the relay driver.

The pump can be powered three ways: Either from the ECM via the relay which itself runs off BAT+ (e.g. hot all the time) w/ 20 amps, or from the engine being on and the oil pressure switch activated (amp unknown but possibly 20) and also supplied from BAT+, or from the module supplied from IGN+ which activates the pump for just a short time anytime the key is first turned on whether the engine is started or not and provides 10 amps. With the engine ignition turned off and of-course engine not running but the pump still on (the undesirable condition) you could check if the dk grn/white off the ECM was hot and if so it would indicate an ECM problem (it will not be back-fed), or pull the relay out which if the pump stopped would indicate a stuck relay, or pull the connector from the oil pressure switch which if that caused the fuel pump to shut off would indicate that switch is bad. Finally and most unlikely, pulling the connector off the module and having the pump turn off would indicate that it's both getting power when it shouldn't via a crossed wire or something and also defective and staying on all the time. Beyond that if the pump is still running, somebody or some thing has done something they shouldn't have and you'd be looking for things like crimp connectors or rodent chewing.

good list

problem. When the tan/white wire is disconnected at the switch - it turns off. If the tan/white wire is connected, you can disconnect all of these simultaneously and the pump still runs: oil pressure switch, relay, computer, AND the hot module. And to be uber clear - by disconnected I mean air gap between the plug and device.

there are no crimp connectors on any wiring anywhere on the truck.
there are no pinched wires between the bed and the frame
there is no rodent damage anywhere.

the ONLY place I can imagine it's getting power is through the ignition circuit... but how... I do not know. there was some PO work done on the column (as evidenced by the removed panels and that the high/low switch is improperly connected).... but nothing obvious.

the next step in this will be to try to short the power wire and hopefully blow a fuse (not burn the truck down).. with that, maybe, I can figure out where the power is coming from.

thanks for the advice, it helps me be sure I'm following the right path... but - let me reiterate... I HATE WIRING. right now I have the dually, the Jeep, and the FJ40 all with some kind of wiring issue. FMBL

[Loren]

The tan/wht wire is a signal for the ECM to know the pump is being powered, e.g. the bearer of bad news if it's hot w/ the engine off, not the cause of it. The dk grn/wht is the relay driver.

The pump can be powered three ways: Either from the ECM via the relay which itself runs off BAT+ (e.g. hot all the time) w/ 20 amps, or from the engine being on and the oil pressure switch activated (amp unknown but possibly 20) and also supplied from BAT+, or from the module supplied from IGN+ which activates the pump for just a short time anytime the key is first turned on whether the engine is started or not and provides 10 amps. With the engine ignition turned off and of-course engine not running but the pump still on (the undesirable condition) you could check if the dk grn/white off the ECM was hot and if so it would indicate an ECM problem (it will not be back-fed), or pull the relay out which if the pump stopped would indicate a stuck relay, or pull the connector from the oil pressure switch which if that caused the fuel pump to shut off would indicate that switch is bad. Finally and most unlikely, pulling the connector off the module and having the pump turn off would indicate that it's both getting power when it shouldn't via a crossed wire or something and also defective and staying on all the time. Beyond that if the pump is still running, somebody or some thing has done something they shouldn't have and you'd be looking for things like crimp connectors or rodent chewing.

[SuperBuickGuy]

still have no idea why that wire is powered with ignition off
but added more to the plate... bought this for $200
2001 4L80e

fluid smells fine - and came with torque converter

very tempted to plug in the stand alone megasquirt controller and stuff it in the truck... 25% overdrive would be nice

[SuperBuickGuy]

it got pretty warm so I didn't get back to this today... tomorrow I'll start tracing why I've got power to the tan/white wire 24/7

[silver_bullet]

[SuperBuickGuy]

for some reason the wire going to the switch is staying hot at all times. I'm pretty sure the tank switch is supposed to be on the 'switched on' power side of the fuse panel - thus it is doubly confusing as to why this is happening. The wire that's staying hot is the tan/white wire

so now the question is whether or not the computer is staying on (not going to sleep) or there is a fault within the computer. I've checked the fuel module, replaced the tank switch, checked the relay...

hmm, but now I'm thinking that maybe if a ground was bad that it would never shut off.... easy enough to check (oh and it's 109 degrees outside right now so that will slow things down a bit).

[SuperBuickGuy]

Bad relay?....just a guess...

nope

here's the image of the wiring harness... I'll explain where I'm at in the next post

[silver_bullet]

Bad relay?....just a guess...

[SuperBuickGuy]

and second problem. fuel pump remains on when the key is in the off position.... (and for bonus fun, whatever tank the switch says... that pump is on).

[DanStokes]

Looks good to me as a functional starting point. Guessing she's not going on the show circuit.

[SuperBuickGuy]

time to assemble a mirror

and assembled

and together


thankfully Dan can't see the terrible work I did to make it one color


but it's together enough to use it and that was the point. Soon enough I'll blow it apart and paint it correctly - but until then....

[SuperBuickGuy]

A/C
the pump was frozen, turns out it's still good so I have a spare...

and here's the problem. They put the wrong seals at the back of the pump... turns out the ones sent with the new pump were wrong too....

new pump - it's aluminum for weight savings

installed

and now working