The temperature gauge, fuel gauge and back up lights on my 88 Hardbody are all out. Looks like all three are on the same circuit according to the wiring diagram. Can't find any fuses blown or loose connections. Looked for a short circuit since all would come and go while driving it. I did find wires melted at the PTC Relay. Any idea what the PTC relay controls on the 1988 Nissan or a likely place to begin finding this problem?

Hmmm... I've got the exact same prob on my 96 HB. I thought it was related to a parts failure associated with the MIL Recall Campaign that I posted in the Hardbody section early last week; a number of the parts are on the same fuse. Got that taken care of today, but the meters and the reverse lights are still out. Whatever the cause is for me it's popping the fuse. There is quite a bit of equipment running on that circuit and I haven't tracked it down yet.

Budman, if you find it let us know, and I'll do the same.

Did a little research on the WWW last night found several posts saying if both the temp gauge and fuel gauge do not work, other than a blown fuse the problem most likely is the voltage regulator since both gauges work off low volts. My Haynes repair manual says to check the output of the altenator and if it is over 15.5 volts, the IC regulator is bad, which is located inside the alt. Mine read over 17 volts. I'll begin looking at my options to repair that this week.

Definately needs a rebuild or new one swapped in w/ that output voltage.

Interestingly, I noticed that the "Batt" on the dash was on (weakly though) and thought that that might be a potential source (too much current) for the fuse problem, so I checked the alty; came in at 13.75v at idle. Perhaps it's an issue at off idle.

Thanks for the hint Budman,

Switched out the altenator last night which solved the hi volts problem but not the gauge problem. They both still come on and go off randomly. I saw a post somewhere about another voltage limiter on the rear of the instrument cluster, anyone have experience with that?

Well, I think I sorted out the instrument panel problem. Earlier I posted that I had a MIL that indicated a fault in the Tank Fuel Temp Sensor (0402). A couple of days later my dash went out. Actually it was a fuse. Changed the fuse, drove 50 feet and it popped again. I thus surmised, after reading what’s on the circuit for that fuse, that the fuel temp sensor had probably shorted and was causing a high-current drain, popping the fuse. Thus, I hoped that the installation of the new components associated with the TSB I wrote about earlier would fix the short, and therefore my meter problem. I told my service rep to have the tech replace the fuse after the installation of all the new gadgets. Well, the guy who did the work said he did (using my spare 15 amp fuse in the 10 amp circuit no less) and that it popped immediately. I was not happy with that news for it meant that there were two separate problems, and only one was fixed, allegedly. So, I drove home and thought about the possible sources of the problem. The next day I put a fuse in the circuit and turned the key to “on” which allows the instrument panel to work without popping the fuse. I noticed that the MIL was on. So I pulled the codes and got 0104, 0807, and 0402! 0402, that’s what I went in for in the first place, that should have been fixed! So now I’m a bit ticked. The guy said the truck checked out ok, that everything had been fixed except the fuse problem, but now there are codes flashing on the ‘puter relating to things that were just changed!!!

So, for the next few days I drove around without any gauges while I traced every component on the #11 fuse circuit. I could find absolutely nothing wrong; no unconnected harnesses, no melted wires, no frayed ends, no nicks…nothing. During this period I began forming a hypothesis: that there was indeed nothing wrong, that the reason for the codes was because there was no fuse in the circuit; no fuse meant that there was no power to the sensors, which meant no sensor report to the computer to say everything is all right.

Put the fuse in, cleared the computer, then drove around the block, and the fuse didn’t pop!!! Parked, turned everything off, then drove around again. Then one more time. No codes, no popped fuse, yeah! So, pending a more long-term test, it would seem that everything is back to normal with Indy (that’s my truck).