Gauges

In an attempt to troubleshoot/fix a non-working fuel gauge over the weekend I removed the instrument panel. Long story short, none of the gauges are working now! Temp gauge worked fine before. Could it be the wiring harness is so old that just messing with it a little made it crap out? Only thing I did was unplug everything from the back of the panel and plug it back in after I put a new fuel gauge in. Any suggestions before I pull it all back out to try to see whats going on? Oh, and for the fuel gauge, I replaced the sending unit a while back, still didn't work. Used a test light to see if the sending unit was getting anything and it lit up... so I figured it must be the gauge. Still doesn't work...
 
make sure the fuel gauge was centered in the housing,if not it will short out and fry the IVR. I didnt center mine and have been chacing a problem with the fuel gauge now for 2 years(really dont mess with it that often) The cluster gets grounded to the dash when its screwed in and the IVR will step down the voltage from 12V to a pulsing 5/6 volts.So cherck for power at the IVR and then go from there.
 
When you say centered in the housing, how exact does it have to be? Sorry for asking a dumb question but what is the IVR and where can I find it? I'm new to this but am learning quick. Like this past weekend I learned that I shouldn't have messed with the instrument panel and that a broken fuel gauge wasn't so bad!
 
It's the brown rectangular part attached to the back of the large, right gauge. The gauges can;t handle the higher voltage of 12V so this "device" brings down the voltage to a useable level.

DSC00602.webp
 
if you noticed when you pulled the gauge,there should have been some carboard "washers" to insulate the nuts from grounding on the housing,also the holes where the gauge studs go through are slotted,they need to be right in the middle. Also smell the Instrument Voltage Regultor,see if it smells burnt.
 
Thanks for all the tips. I remember that when I pulled the contacts off the IVR they weren't easy to get off. I won't be able to pull it back out until this weekend. If it does smell burnt, is it something that can be replaced or do I have to get an entire new instrument panel? I don't remember how it was attatched to the back of the panel.
 
Thanks for all the tips. I remember that when I pulled the contacts off the IVR they weren't easy to get off. I won't be able to pull it back out until this weekend. If it does smell burnt, is it something that can be replaced or do I have to get an entire new instrument panel? I don't remember how it was attatched to the back of the panel.
The IVR is about 40 bucks and made in Taiwan or China, and its also a piece of crap. I bought one and the contact broke right off as soon as ity came out of the box.You can make one from a voltage regulator from radio shack for about 2 bucks.Its attatched with a1/4" or 9"32 bolt to the housing like in the photo above.
 
Thanks for all the tips. I remember that when I pulled the contacts off the IVR they weren't easy to get off. I won't be able to pull it back out until this weekend. If it does smell burnt, is it something that can be replaced or do I have to get an entire new instrument panel? I don't remember how it was attatched to the back of the panel.
The IVR is about 40 bucks and made in Taiwan or China, and its also a piece of crap. I bought one and the contact broke right off as soon as ity came out of the box.You can make one from a voltage regulator from radio shack for about 2 bucks.Its attatched with a1/4" or 9"32 bolt to the housing like in the photo above.
 
This IVR, are they used on a 70 Mach I. My fuel gauge does not go above 1/4 tank when full, the temp gauge is not working at all. I replaced the sending unit in the tank today, that wasn't it. Maybe the IVR is my problem if I have one.

Thanks