Yet another electrical/wiring question

[DJPoop]

I've been through every past thread I could find to try and figure this out, but I'm stumped. Plus I'm a noob to Broncos and auto mechanics in general, but have been enjoying tinkering around after spending hours on this forum and watching youtube videos.

My latest project was the voltmeter mod to replace the alt gauge, since I upgraded to a 3g alternator. I followed Steve83's awesome guide and after a few hours, voila, I had it installed in the cluster.

While I was at it and had the cluster out, I also swapped in a new IVR, since my gauges have never worked. I used one of the Scott Drake constant solid state IVRs. I hooked everything up and all of the gauges finally worked (awesome!), plus well as the voltmeter was working (I just soldered a wire from the positive post of the gauge to the 12v input of the IVR). The only problem was that while the gauges were working, all of the cluster lights were on: both turn signal lights, as if the headlights were switched on, plus the red light at the top (high beam light?).

I have an American Autowire harness that was installed professionally when I bought the truck, so I checked the manual and saw that the ground wire on the diagram below was not connected to anything and the terminal end of the wire was taped off (click the thumbnail for full size).


I figured that must have been the issue so I just connected it to the negative end of the new voltmeter since it's a long post and was easy to reach, which contacts the housing anyway, so it seemed like it wouldn't be a problem. When I cranked it to see if that did the job, I heard a pop from behind the gauges and they all went dead and the cluster lights that previously just stayed on all went off. I disconnected that ground wire and nothing, so I assumed I must have blown the IVR and that was why it was taped off to begin with, who knows???

At that point I was pissed, so I just ordered a new IVR on Amazon since have Prime and wanted it ASAP. Here's the one I got: https://www.amazon.com/gp/product/B000IYU9MC/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

So fast forward to today, I swapped in the new IVR and hooked up everything except for the voltmeter (actually everything was still hooked up, so I just plugged the two wires into the IVR). I also added a new ground wire to the cluster housing; figuring that might have been the problem last time. After my last experience, I tried it out first without the new ground wire attached to anything. The oil and temp gauges spiked, fuel did nothing, and again, all the lights on the cluster came on. So then I hooked up the new dedicated ground wire that I added (not the one from the harness), and the lights went off, temp and oil gauges went to zero and fuel just stayed at zero. Just for the hell of it, I even connected the damn random ground wire from the harness that I think messed everything up before, and although I didn't blow anything this time, it ended up the same as just using the dedicated ground.

Here's a short clip showing what I mean in case my explanation is too garbled. Halfway through is when I touch the new ground connected to the back of the housing to a screw on the dash. Strangely enough, a few seconds later, after the video ends, all the lights come back on and the temp and oil spike again: https://youtu.be/2Nr71s1bnws Pay no attention to the voltmeter, it's not currently powered.

Although I doubt it has anything to do with it, just to rule things out, I did install a battery cutoff switch in the glove box. So now I've got the negative cable running from the battery terminal through the firewall to the switch, and another cable going from the other side of the switch through the firewall to the engine block, and then from there to the frame. I was thinking it wouldn't hurt to run another wire from the switch to the underside of the dash, but haven't done that yet.

My novice self figures this issue with the gauges is either still some problem with grounding, or possibly I need to try to mess with the little adjustment knob on the back of the IVR. Hopefully the experts here can point me in the right direction because I'm about to start throwing crap around my garage if I can't get this figured out.

 

[DJPoop]

Ok, so I just grounded the dash directly off of the battery, and then grounded the cluster. Same result....the lights don't all stay on, but none of the gauges work. But at least I think it's safe to assume it's properly grounded when either the new ground I attached to the housing or the one from the harness is connected. What's next, fiddle with the little knob on the back of the IVR?

 

[September 1972]

The gauge circuit is very low volts and very low current and sensitive to resistance. That's a good idea to add grounds however gauges won't work well with a dedicated ground as you found out. The body shell is near zero resistance and you want to use what ford used.

I built and installed a 2 cable negative battery terminal. I stuffed a greased number 1 SAE cable and a number 4 cable into a one OT negative battery terminal and crushed it in my die press to 10K pounds, it ain't moving ever. Next the best shrink wrap was used to seal it. The 4 gauge loops under and is connected to a fender bolt on the underside secured with a washer and nut. Done.

If you want a pic of badass cables that will lift an engine I'll send it to you tomorrow. If someone wants to bet 500 dollars that my cable won't lift 500 pounds with grease on the copper wire inside the terminal, bring it on.

The gauges will complete their journey and the gauges will work if the cluster is grounded as Ford intended and the gauges are grounded to the cluster. It's easy.

 

[DJPoop]

The gauge circuit is very low volts and very low current and sensitive to resistance. That's a good idea to add grounds however gauges won't work well with a dedicated ground as you found out. The body shell is near zero resistance and you want to use what ford used.

I built and installed a 2 cable negative battery terminal. I stuffed a greased number 1 SAE cable and a number 4 cable into a one OT negative battery terminal and crushed it in my die press to 10K pounds, it ain't moving ever. Next the best shrink wrap was used to seal it. The 4 gauge loops under and is connected to a fender bolt on the underside secured with a washer and nut. Done.

If you want a pic of badass cables that will lift an engine I'll send it to you tomorrow. If someone wants to bet 500 dollars that my cable won't lift 500 pounds with grease on the copper wire inside the terminal, bring it on.

The gauges will complete their journey and the gauges will work if the cluster is grounded as Ford intended and the gauges are grounded to the cluster. It's easy.

So what would you say is the best solution to get my gauges working? It's weird they seemed to work for a while with the last IVR, other than all the lights being on.

 

[Steve83]

While I was at it and had the cluster out, I also...

This is why it's better to do just ONE modification at a time: so you know that each one works, and which one caused a problem.

I have an American Autowire harness that was installed professionally...

That's going to make diagnosis harder because neither you nor we know how the truck is actually wired at this point. You can hope the installer did it by-the-book, but the loose wire that you've already found suggests he didn't.

At this point, I recommend you find a pro (maybe a stereo/alarm installer who's comfortable with non-stock wiring) to find/fix the problem(s).

What is that diagram supposed to show? What is Connector A?

I heard a pop from behind the gauges and they all went dead...

Did you check all the fuses & fusible links?

...I assumed...

You should really DIAGNOSE.

...hooked up everything except for the voltmeter (actually everything was still hooked up, so I just plugged the two wires into the IVR).

Are you saying you transferred the 2 voltmeter wires (positive & negative) to the ICVR's 2 main terminals (positive & regulated output)? That could explain all your subsequent symptoms, and why the ICVR isn't working.

The oil and temp gauges spiked...

That would happen if you put a 12V wire on the side that's supposed to be regulated near 6V.

...all the lights on the cluster came on.

That's typical of 12V on the ground side of small bulbs in a circuit with larger bulbs (in the marker lights). So that goes back to what you did with the voltmeter wires on the ICVR.

...just to rule things out, I did install a battery cutoff switch in the glove box.

Are you saying you added that AFTER all the cluster problems?

...mess with the little adjustment knob on the back of the IVR

I wouldn't recommend that.

If you don't want to take it to a pro, step back & take a breath... Then try to restore it all to the way it worked before (disconnect the voltmeter, and put a normal ICVR in) and start fresh. Take LOTS of pics as you work, and post them. Use a DMM or 12V test light to check the state of each wire (key off, key on; headlights off/on; etc.) so you KNOW what it does before you modify it.

 

[DirtDonk]

First, that ground wire is intended to be grounded. Not be the ground for something.
At least that's my take on it. Is that a sheet from the American Autowire instructions?

Can't say for sure of anything yet, as Steve was saying. But that pop might have been the new solid-state IVR going poop.
Or not...%)

More diagnosing is called for. As said, revert it back to where it was when it all worked (even though the lights were all on) and see what happens. If you already did that and nothing happens with the gauges, you need to test the IVR to see if it's working.
And while you're at it, you should test your old one too. Might be fine and there are other issues causing the gauges to not work. Like not having sufficient grounding between the cluster and dash, between the dash and body, and between the body and battery. So check all that while you're at it too.

Easy. Should be done in five minutes.... I mean "months" easy!;D

Paul

 

[Viperwolf1]

The lights were on because they were the only ground path until the ground wire was attached. The lights also limited the current through the IVR. When the good ground wire was attached the IVR blew due to excessive current through it (light bulbs no longer limiting current). That can only occur if one or more of the sender wires or gauges has a problem, like a short directly to ground. I recommend removing the oil, temp and fuel sender wires and measuring resistance from them to a good ground. You should see at least 10 ohms but will see much more (maybe in the hundreds of ohms)on the oil and temp. If you get anything less than 10 ohms you found the problem circuit.

You can also test the gauge resistance while the sender wires are off. You should see about 18 ohms across the gauge terminals.

 

[September 1972]

Add the grounds and clean existing grounds and clean every connector and fuse and with a straight pin soldered to a lead check continuity across all connectors and it might fix itself and if not you are familiar with the thing. Next break down circuits and check for hot drops, you seem smart, "figure it out" as Walter White would say.

 

[DJPoop]

Thanks folks. All Great advice.

Stevie, special thanks for the thorough post to addresses every aspect of where I screwed the pooch on this one, lol. As for your questions, I only connected the positive end of the voltmeter to the 12v end of the IVR. So I meant I had the wire from the harness for the IVR and the voltmeter + wire going to the IVR. Duly noted on trying to tackle one thing at a time too.

Paul, yes that pic I posted above is from the wiring harness instructions.

One thing I forgot to mention as well that could certainly be affecting things (since trying to deal with these gauges has turned me into a blathering moron) is the fact that there is a shit ton of extra wiring behind the dash. I've got an aftermarket stereo with an external amp, four speakers, a powered sub woofer, and an alarm system with a proximity sensor, tilt sensor and battery backup. I had that installed when I first got the truck before the gauges were working, and I know there are grounds for all that shit connected in various places. Since I've started this odyssey into Gaugeland, the rear speakers are now buzzing slightly, so they're getting some noise from something I've done under there. Fucking awesome.

As I was thinking about this last night though, I'm wondering if one of the gauges could be grounding to the cluster and if that might be causing my problems here. When I had the cluster out to do the voltmeter, I took it apart; not fully, but enough to take the glass, or in my case, plexiglass face that the PO must have installed, out so that I could polish it up. It might be a good idea to take the cluster out again and make sure none of the gauges shifted around inside and are now grounding to the cluster.

Fun times.......

EDIT - Oh yeah, I was also trying to test the IVRs on the bench last night, so I rigged up a test battery using a 9v and some AAs so they were outputting a little over 13v. Then I connected the + end of the battery pack to the 12v end of the IVR, and used a multimeter with the red wire on the regulated terminal of the IVR and the black wire to the - end of the battery pack. Both the original IVR and the solid state were showing over 12v coming out of the regulated side. Not sure if I did this wrong since the - end of the multimeter was going to the - end of the battery rather than to another ground source, but I figured if one or both the IVRs were good, they should have been outputting ~5v to the multimeter.

EDIT 2 - If one or more of the gauges could be grounding to the cluster, is there anything wrong with insulating them better by wrapping them in electrical tape or something?

 

[Steve83]

I've got an aftermarket stereo with an external amp, four speakers, a powered sub woofer, and an alarm system with a proximity sensor, tilt sensor and battery backup.

All of that needs to be in your signature. Look at Paul's & Viperwolf1's. %)

Then I connected the + end of the battery pack to the 12v end of the IVR, and used a multimeter with the red wire on the regulated terminal of the IVR and the black wire to the - end of the battery pack.

You didn't have it hooked up correctly, so it wasn't working. You should ALSO have had the battery (-) going to the ICVR case. That's what allows it to cycle. But it doesn't actually deliver 6V; it pulses 12V on & off, giving an average of 6V.

...is there anything wrong with insulating them better by wrapping them in electrical tape or something?

It's not a repair; it's a patch. And a weak one. At any moment, the tape could wear through, causing the short to return. Especially at the gauge mounting screws. FIND the problem. If you're not sure, post a LOT of pics.

 

[DJPoop]

All of that needs to be in your signature. Look at Paul's & Viperwolf1's. %)You didn't have it hooked up correctly, so it wasn't working. You should ALSO have had the battery (-) going to the ICVR case. That's what allows it to cycle. But it doesn't actually deliver 6V; it pulses 12V on & off, giving an average of 6V.It's not a repair; it's a patch. And a weak one. At any moment, the tape could wear through, causing the short to return. Especially at the gauge mounting screws. FIND the problem. If you're not sure, post a LOT of pics.

Sounds good. I'll post pics as soon as I can. I just dropped it off this morning at my mechanic's shop to install disc brakes, which I didn't trust myself attempting to tackle. I'm sure after reading this tread all can agree that was probably a good call, lol. Will add my info to my sig as well. Thanks again for the advice.