Roach Coach VII

[bobslaven]

Fellow Bumpside Warriors,
Most of the wiring in Billy Bob's 1970 F-250 Custom 4x4 (gauges, not idiot lights) was a dumpster fire. I used the Painless kit to rewire the whole thing. It took a while, but I learned a lot and (mostly) enjoyed it. Most everything works meow, but I'm troubleshooting some stuff - mostly up in the instrument cluster. Armed with my trusty multimeter, a shop manual and your help, I'm sure I'll finish this job eventually.
Some of these questions may be dumb, but I'm not a smart man. Apologies.
1. Should my ammeter work all the time? Those are the only two instrument cluster wires with voltage when the ignition is off.
2. Speaking of ignition off, please confirm my brake lamps should work then.
3. Is my dome light my courtesy lamp? Should I have a bulb up under the dash like (I think) the Bronco had? Was that an option for fancier trim groups?
4. If my courtesy lamp switches were working, wouldn't they make the dome light come on anytime I open one of my doors?
5. Is it ridiculously difficult for you to get to your oil pressure sending unit? Do any of you have a good source for a low profile version, or maybe an oil filter adapter that mounts it on the drivers side of the truck instead of the top?
6. The way I read it, if I've got a gauge then I shouldn't run a wire from the stator to the voltage regulator. The Painless kit said to do it though. I did (before I read the shop manual). It seems to be working and charging and reading correctly on the ammeter. I don't really know what that stator post and wire do for me (field/ground/battery make sense). Did I mess up?
My current theory is I've got a bad IPVR. Hopefully that solves my gauge issues.
I thought I'd leave this as a running thread until my wiring job is complete. I'm sure I'm going to come back asking for help soon.
Thanks in advance for any help you can give.

Billy Bob

[sargentrs]

I can't answer everything but I do know a couple:

2. Speaking of ignition off, please confirm my brake lamps should work then. Brake lights should work all the time. That circuit feeds straight from the fuse box.
3. Is my dome light my courtesy lamp? Should I have a bulb up under the dash like (I think) the Bronco had? Was that an option for fancier trim groups? Only interior light I know of is the dome light.
4. If my courtesy lamp switches were working, wouldn't they make the dome light come on anytime I open one of my doors? Yes
5. Is it ridiculously difficult for you to get to your oil pressure sending unit? Do any of you have a good source for a low profile version, or maybe an oil filter adapter that mounts it on the drivers side of the truck instead of the top? I've used these before https://www.summitracing.com/parts/sum- ... LsQAvD_BwE
Billy Bob

[bobslaven]

sargentrs,
Rock on. I was hoping you'd chime in.
Good tip on the extension, not sure if it'll fit in there but it's worth checking out.
Making a list, solving them one at a time...
Thanks for helping.

Harrumph!
Billy Bob

[sargentrs]

Not sure what engine you have but fits easily on a small block. I like that you can install it using a ratchet and deep wall socket. Good luck!

[bobslaven]

Unfortunately there's no way that extender is going to fit. The sender is right up under the driver side head on my 360...and behind the power steering pump. Got another plan for the next time I take that sender off...which hopefully won't be soon.

[bobslaven]

Fellas,
Looks like the old truck won the last couple rounds. I'm in need of some help.
Again, 1970 F250 Custom 4x4 360 with gauges. Recently rewired with Painless kit. Most stuff works, but the temp/oil/fuel gauges are dead.
I did some research (shop manual then FORDification) and tested the IVR by removing the wire at the temp and fuel senders (oil is too tough to get to) and turning on the ignition. The temp wire went from zero to about 3 volts but the gauge on the cluster didn't move. The voltage at the fuel sender didn't budge from zero. I tested the continuity in the fuel wire and it's good all the way to the orange fuel sender wire at the instrument cluster connector. I replaced the IVR (twice), hoping that would fix it. No change. Well, not true, now I get no power to the wire (black and green) that plugs into the circuit board. Like the new IVR blew a fuse. I checked the fuse, it looks to be in good condition, but I tried 2 more...still no voltage input for the IVR with the ignition on.
I traced all the lines in the printed circuit board and the continuity is good so I figured the PCB (which is new) is functional. However, even when it DID get voltage to the IVR, none seemed to arrive at the gauges, so maybe the PCB is bad - or the IVR.
I also thought maybe the temp/fuel/oil pressure gauges might be bad. Seems unlikely though. If I could put some voltage on the input side of the gauge they should max out be so long as that voltage is 5 or greater, right?
Oh, if I put 12v on an IVR, it should put out about 5, right? What's the best way to test these (off of the truck)?
Anybody see this before? I scoured the electrical threads and came up empty. Any tips would be much appreciated.

Billy Bob

[390FE1972]

Just a question, do you have the 1970 IVPR or a 71 & 72 IVPR? This thread talks about a difference in the part.
http://www.fordification.com/forum/view ... 9d14add117

Regards

[bobslaven]

FORDification,
Excellent link. Thanks to 390fe1972. I love it here. I haven't seen that particular thread.
I've actually tried 2 different new IVRs, neither one cost me near 85$. However, mine look more like the 70 version from the picture (based upon the location of that extra circle dimple thingie near the output post).
Update to last night's post though. Upon further review, in daylight conditions, my fuses weren't so good after all. The one for the gauges was blown, so I tried another. It blew as soon as I turned on the ignition.
Now I'm no electrical scientist, but it seems like something in that circuit is shorted out. Something up on the instrument cluster (that circuit serves the choke too, but mine's manual and that wire is buttoned up pretty good). If I had one (or 3) bad gauges, could they cause that fuse to blow? How about the printed circuit board? Final suspect seems like the IPVR. Would a 1972 version cause that fuse to blow? Could it damage anything else? I don't have that wire-wrapped device on mine - radio choke as I understand it. Could that cause my problem?
Based upon a conversation with the folks at Painless, I figured I'd go remove the gauges, replace the fuse, and see if it blows then. Make sense?
Thanks again.

Billy Bob

[cash667]

You can test the IPVR on the bench.
Put +12V on the Input (where the green/black wire is normally connected) an connect your voltmeter to the Output and minus battery. Some Aftermarket IPVR MUST have their housing grounded.

The Voltmeter should Show about 5V or slow alternating between 5V and a lower voltage.

If this is ok connect the IPVR back to the cluster an feed 12V through the green/Black wire (with a fuse at some Point- just to be sure).
To check your gages you need to connect your sending unit wires to ground and you will see the gauges moving to full etc position.
For example fuel gauge Test:
IPVR installed on cluster and fed with 12V through black/green wire. Cluster housing connected to ground.
Orange wire from cluster connected to groud should bring the fuel level up.
As you see the needle moving up to it’s max value, disconnect the orange wire from ground to prevent damage to your gauge. It’s just for short checking if the gauges are reacting.

Hope this was not to confusing.

Cheers from germany
Chris

[bobslaven]

Great tip. Thanks so much.

Today I removed the temp, oil and fuel gauges. Replaced the 10A fuse and turned on the ignition. Got good power to the PCB, no blown fuses, and voltage out of the IPVR. Now it's not a steady 5 like I expected. Seems to fluctuates between about 0 and 10, but at least it produces something and doesn't blow fuses. Seems to me like at least one of my gauges is bad...and possibly that IPVR as well.

Going to follow your instructions to find my best IPVR and then test one gauge at a time.

[bobslaven]

Followed cash667's advice. One of my IPVRs makes a steady 5v. Solid.
Tested my gauges off the truck by applying 12v...they move up.
So it seems to me like the IPVR is good, the PCB is good, and the gauges work. So, why do I blow a fuse every time I put them all together?

New problem though - cigar lighter fuse blows every time the truck gets power on it. Just started this evening. Read another thread and discovered mine (a replacement) has a grounding post on it. I'll try that out tomorrow and see if that fixes it.

[390FE1972]

From reading some of the post on the website the IPVR should get a pulse and be around 5V, but with a pulse, so not a constant 5V. Here is a thread that talks about that, plus another thread that talks about an adjustment on some of the IPVR's.
http://www.fordification.com/forum/view ... f=8&t=9698
http://www.fordification.com/forum/view ... =8&t=61164

Regards

[cash667]

Followed cash667's advice. One of my IPVRs makes a steady 5v. Solid.
Tested my gauges off the truck by applying 12v...they move up.
So it seems to me like the IPVR is good, the PCB is good, and the gauges work. So, why do I blow a fuse every time I put them all together?

New problem though - cigar lighter fuse blows every time the truck gets power on it. Just started this evening. Read another thread and discovered mine (a replacement) has a grounding post on it. I'll try that out tomorrow and see if that fixes it.

Please do NOT power gauges directly with 12v! The IPVR is used to drop the power to the gauges down to around 5V.

There are basically two versions of IPVR: mechanical and electronic. The mechanic will output a More or less slow alternating voltage around 5V. The electronic will have a steady reading of about 5V. But the electronic must have its housing grounded!! If not, the Output voltage may Change to much higher values.

As you see in your test, the sending units are basically resistors to ground. They are changing their resistance in accordance to their Reading (water temp, fuel level,...)
This means, the surfaces where they sit in must have good ground connection aswell.

Back to your fuse problem: I do not have an Idea about that. Since you have new wiring it could be everything.
But I think I would start to check every ground connection on every device. Especially ground to cluster and all electrical devices around the dash area.
Bad ground connections are the most common issues on our older cars & trucks

Good luck!
Chris

[bobslaven]

All makes sense. You guys are the greatest. I hope I can help out some other folks one of these days.

Grounded the cigar lighter today, but that didn't fix anything. Putting in the old one did though. Works like a champ.

Got my aux tanks hung up again. They look great. Can't wait to put gas in 'em.

Didn't end up with as much time as hoped for for electrical trouble shooting. Instrument cluster with PCB and IPVR but no instruments seems to work pretty great. I discovered the resistance on the fuel tank wire is about 70 (pretty much on empty, as I understand it), the resistance on the oil pressure starts low and creeps up, got to about 19 ohms. However, the resistance on the temp gauge appears to be extremely high. Like 200. Pretty sure I had the wires on the multimeter hooked up right. If so, that must mean something. Ideas out there?

I've still got a couple oddities in the turn signals. Probably time to work on that junk soon.

[390FE1972]

This youtube from one of our members, Autorestomod, has some interesting information in it in regards to IPVR and testing guages:

https://youtu.be/O2RWXMoBoO8

Regards