Rembrant Posted May 27, 2021 Share Posted May 27, 2021 My three gauges are all reading low. I noticed the other day that all three were dead, as in all hard to the left well below zero. Today, they are working again, but all reading low. Wondering if I should start with new senders or swap out the ICVR first? I can test temp and Oil pressure by touching them to ground ya? Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 27, 2021 Share Posted May 27, 2021 If all three are doing it the common denominator is the ICVR. I'd order the adjustable voltage regulator and make those puppies reliable. And yes, you can test by touching the sender wire to ground. But if the ICVR is working at all it'll usually peg the gauge even if it is wonky. Link to comment Share on other sites More sharing options...
Rembrant Posted May 27, 2021 Author Share Posted May 27, 2021 If all three are doing it the common denominator is the ICVR. I'd order the adjustable voltage regulator and make those puppies reliable. And yes, you can test by touching the sender wire to ground. But if the ICVR is working at all it'll usually peg the gauge even if it is wonky. Gary, Where is the instrument cluster grounded do you know? Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 28, 2021 Share Posted May 28, 2021 Gary, Where is the instrument cluster grounded do you know? Yes, I do know. But it took some sleuthing to prove it. The proof is here. On Page 87 you'll see that Pin 2 of C208A, which is the connector for the gauge cluster, is Circuit 57 and that it is grounded at G701. And on Page 88 you'll see that G701 is "behind instrument panel near right hand side of radio". Link to comment Share on other sites More sharing options...
Rembrant Posted May 29, 2021 Author Share Posted May 29, 2021 Yes, I do know. But it took some sleuthing to prove it. The proof is here. On Page 87 you'll see that Pin 2 of C208A, which is the connector for the gauge cluster, is Circuit 57 and that it is grounded at G701. And on Page 88 you'll see that G701 is "behind instrument panel near right hand side of radio". Swapped the ICVR today and no change, so I grabbed a new coolant temp sender and installed it but haven’t tested yet. Swapped the gauges too and they seem fine. Both oil and coolant gauges peg hard to the right when grounded. More to come. Link to comment Share on other sites More sharing options...
Lima Delta Posted May 30, 2021 Share Posted May 30, 2021 Swapped the ICVR today and no change, so I grabbed a new coolant temp sender and installed it but haven’t tested yet. Swapped the gauges too and they seem fine. Both oil and coolant gauges peg hard to the right when grounded. More to come. Is it usual for the ICVR to suffer intermittent issues, or is it more common for it to just fail outright? Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 30, 2021 Share Posted May 30, 2021 Is it usual for the ICVR to suffer intermittent issues, or is it more common for it to just fail outright? I've not seen an ICVR completely fail. But I have seen them all of a sudden give different readings on all three gauges, only to go back to the previous reading in a bit. However, I can see that they could fail if the contact points in them fail to make as they close. I really like the true voltage regulator I have on Big Blue. My gauges are rock solid and never flinch. So while I scan all the gauges frequently I feel comfortable with the stock gauges now. Link to comment Share on other sites More sharing options...
Rembrant Posted June 6, 2021 Author Share Posted June 6, 2021 Update: I swapped the ICVR with another one and no change. I installed a new coolant temp sender and cleaned up the connections and it is now working great. I cleaned up the connections for the oil pressure sender it is is ok, but reading a little low (I doubt it is the gauge’s fault, but I might swap the sender anyway). However, I noticed today that the gauges were all dead and at the lowest point below zero when I was first driving but they all started working again a little while later. Odd. I did have to boost the truck though, the battery was dead because I forgot the key on the other day. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 7, 2021 Share Posted June 7, 2021 Update: I swapped the ICVR with another one and no change. I installed a new coolant temp sender and cleaned up the connections and it is now working great. I cleaned up the connections for the oil pressure sender it is is ok, but reading a little low (I doubt it is the gauge’s fault, but I might swap the sender anyway). However, I noticed today that the gauges were all dead and at the lowest point below zero when I was first driving but they all started working again a little while later. Odd. I did have to boost the truck though, the battery was dead because I forgot the key on the other day. Sounds like a bad connection in the circuit to the ICVR. Maybe at the gauge cluster? Link to comment Share on other sites More sharing options...
1986F150Six Posted June 8, 2021 Share Posted June 8, 2021 Sounds like a bad connection in the circuit to the ICVR. Maybe at the gauge cluster? Cory, if the ignition switch is sticking, the gauges will not work. When this happens, see if the turn signals work? Jiggle the ignition key. Link to comment Share on other sites More sharing options...
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