farmer52 Posted May 7, 2011 Share Posted May 7, 2011 The list is starting of things that need corrected in my MH. 1. When I turn on the headlamps, the REVERSE and RH TURN indicator lamps illuminate and the fuel gauge goes to F (full). When the headlamps are on HIGH beam, the indicator lamps are brighter. I also noticed the HIGH beam indicator does not work (hopefully a burnt bulb).2. The pyrometer does not register any exhaust temperature. Is the problem with the gauge, thermocouple, or wiring?Anyone have any suggestions on what to check or what are the problems? Thanks! Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
rw613 Posted May 7, 2011 Share Posted May 7, 2011 yep thats a mh and good luck thats the worts thing about the trucks 1 Quote Link to comment Share on other sites More sharing options...
Firemack Posted May 8, 2011 Share Posted May 8, 2011 Farmer 52,Since the MH is Fiberglass (maxiglas), I always look at ground first and see if it is indeed working. To test you need to connect the test light on the hot side of the battery and then check to see if the test light works when you try the ground on each one of the lights. My guess is the headlights are not grounded and is using the other lights to find a ground, and causing the issues. Maybe one of the rest of the team here can explain the Pyrometer issue, I would test like a temp gauge, Make sure you have a good ground, then ground it out and it should make the gauge go to maximum temp. If not then then you should check the wiring to the gauge and the gauge itself. If it does max the gauge when grounded then you need to change the Pyrometer thermocouple. I have 2 MH Pyrometer gauges if you need one.Firemack Quote Link to comment Share on other sites More sharing options...
farmer52 Posted May 8, 2011 Author Share Posted May 8, 2011 Firemack - thanks for the great suggestions. It will be a couple weeks until I can check the ground (out of town on business). Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
farmer52 Posted May 22, 2011 Author Share Posted May 22, 2011 I had a chance to briefly look at the MH on Saturday (the "honey do" list took priority). One thing I noticed is when you toggle the signal switch to headlights, the "high beam" lamp illuminates (as do the headlights). However when I use the dimmer switch to change from low to high beams the "high beam" lamp does not illuminate. The next time I get a chance I am going to try to disconnect the dimmer switch and see if this resolves the issue. Could there be short in the dimmer switch? I agree it is probably a ground issue but finding it will not be easy. Any additional suggestions are appreciated. Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
heavyhauler Posted May 22, 2011 Share Posted May 22, 2011 Grounding issues with those cabs was always a problem. There are several metal strips that run through the cab and serve as both reinforcement and grounding points. There may be other problems but the I think getting the grounding issues solved would be a good place to start. We are parting out some stuff on the MH pictured. Let us know if and what you need.John Quote Link to comment Share on other sites More sharing options...
Greg Rider Posted May 22, 2011 Share Posted May 22, 2011 Do you still have your blue truck? I thought you were selling it. Good to hear from you. Quote #1 on A-model registryIf I drink because of work, why can't I drink at work? Link to comment Share on other sites More sharing options...
farmer52 Posted May 23, 2011 Author Share Posted May 23, 2011 Do you still have your blue truck? I thought you were selling it. Good to hear from you.Hi Greg! Sold it but bought another one (just like the other one only 7 VINs newer). I am a glutton for punishment! Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
farmer52 Posted June 11, 2011 Author Share Posted June 11, 2011 The list is starting of things that need corrected in my MH. 1. When I turn on the headlamps, the REVERSE and RH TURN indicator lamps illuminate and the fuel gauge goes to F (full). When the headlamps are on HIGH beam, the indicator lamps are brighter. I also noticed the HIGH beam indicator does not work (hopefully a burnt bulb).2. The pyrometer does not register any exhaust temperature. Is the problem with the gauge, thermocouple, or wiring?Anyone have any suggestions on what to check or what are the problems? Thanks!I was able to get the light/gauge issue resolved. I jumpered a wire from the fuel gauge ground to the panel screw. Next week will be the "shakedown" run to Macungie.I changed the pyrometer and that did not resolve the temperature issue. I ordered a new thermocouple ($70) which I hope fixes this one. Thermocouple will be in next week and I will install it before I head to PA.I also installed a new radio. The new one is about an inch deeper than the old one. I had to cram 10 pounds of crap into a 5 pound bag. Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
farmer52 Posted June 16, 2011 Author Share Posted June 16, 2011 I was able to get the light/gauge issue resolved. I jumpered a wire from the fuel gauge ground to the panel screw. Next week will be the "shakedown" run to Macungie.I changed the pyrometer and that did not resolve the temperature issue. I ordered a new thermocouple ($70) which I hope fixes this one. Thermocouple will be in next week and I will install it before I head to PA.I also installed a new radio. The new one is about an inch deeper than the old one. I had to cram 10 pounds of crap into a 5 pound bag. Well I am batting 1000 - got the pyrometer fixed. During removal of the old thermocouple I broke the fitting (I don't think it was ever changed). I had to drill out the hole and retap it. I installed the new thermocouple. When I connected the wiring lead I noticed one of the wires was broken. So I spliced the wires and checked it out. IT WORKS! The problem was the wiring harness but at least I have a new thermocouple and fitting. Life is good! Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
Rhonda Z Posted September 24, 2019 Share Posted September 24, 2019 Hi, I have a 2005 mack granite and a few times a week the lighting bolt comes on and at the same time the pyrometer stops working. Truck seems to be running fine. Could this be a bad ground? Help its freaking me out Thanks, Rhonda Z Quote Link to comment Share on other sites More sharing options...
LilMartian Posted September 24, 2019 Share Posted September 24, 2019 Most likely the jumper or sensor have gone bad. Ohm the sensor out, if it’s shorted, will be open. Pigtails will corrode in the connector sometimes. Located behind the coolant tank. Quote And you thought only NASA had rocket scientist!!!! Link to comment Share on other sites More sharing options...
Rhonda Z Posted September 24, 2019 Share Posted September 24, 2019 Ty very much will try it Quote Link to comment Share on other sites More sharing options...
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