Deere Mack Posted April 15, 2014 Share Posted April 15, 2014 Hello everyone! I'm rained out here in Bama today and trying to fix a couple odd things on the '79 RD dump. The truck still has the original pyrometer installed but it's not wired up properly. As you can see in the picture, it's got two electrical studs, a small one and a larger one. The light socket and power for it are seperate. Where do the yellow and red pyro wires go and how do you bring power into it? The previous owner had replaced the pyro wire and just wired it in straight to the probe and didn't bring any power to it...??? Quote Link to comment https://www.bigmacktrucks.com/topic/35417-hewitt-pyrometer-wiring/ Share on other sites More sharing options...
j hancock Posted April 15, 2014 Share Posted April 15, 2014 Maybe this will help. There is a spot to click for installation information above the pictures of the gauges. Hewitts don't need power.http://www.hewittindustries.com/pyrometers.html Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/35417-hewitt-pyrometer-wiring/#findComment-242103 Share on other sites More sharing options...
Deere Mack Posted April 15, 2014 Author Share Posted April 15, 2014 Maybe this will help. There is a spot to click for installation information above the pictures of the gauges. Hewitts don't need power.http://www.hewittindustries.com/pyrometers.htmlI was all over that website and didn't see that link untill now. Thanks, who would have thought, no power. I wonder if they require a special thermocouple? Quote Link to comment https://www.bigmacktrucks.com/topic/35417-hewitt-pyrometer-wiring/#findComment-242104 Share on other sites More sharing options...
Deere Mack Posted April 15, 2014 Author Share Posted April 15, 2014 Just in case the link ever gets removed here's the installation document.180-0054 Pyrometer Installation Instructions rev 07-12.pdf Quote Link to comment https://www.bigmacktrucks.com/topic/35417-hewitt-pyrometer-wiring/#findComment-242105 Share on other sites More sharing options...
Deere Mack Posted April 15, 2014 Author Share Posted April 15, 2014 Just to show how I got confused and still are. Here's the wiring diagram for my truck and I have highlighted the confusion. Quote Link to comment https://www.bigmacktrucks.com/topic/35417-hewitt-pyrometer-wiring/#findComment-242112 Share on other sites More sharing options...
Bobby j Posted April 16, 2014 Share Posted April 16, 2014 Years ago at Overnite the pyrometers on our fmodels had three parts only....... The gauge on dash, the wiring harness and the probe that screwed into the turbo header pipe......the harness goes straight from gauge to probe there is two small machine screws and nuts to hook it together and if I remember correctly there is a heat shrink made onto the probe once you hook it up to keep elements out of connections......bobby j. Quote Link to comment https://www.bigmacktrucks.com/topic/35417-hewitt-pyrometer-wiring/#findComment-242234 Share on other sites More sharing options...
e9500v8 Posted April 27, 2014 Share Posted April 27, 2014 I still use Hewitt pyros today they are the best made. There customer service is impeccable ! Love all there products! Just give them a jingle tell them what ya need and in days they will be in the mailbox! Quote Link to comment https://www.bigmacktrucks.com/topic/35417-hewitt-pyrometer-wiring/#findComment-243454 Share on other sites More sharing options...
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