13BT glowscreen voltage

VE6LLZ · 01-06-09, 05:34 PM

I am in the process of wiring in a momentary switch for my glow screen as my timer and/or relays are suspect. The power wires coming from the relays were wired incorrectly resulting in a short. While trying to "fix" the problem I think I smoked the timer. So, what I would like to know is what voltage should I be measuring at the glowscreen? I assume 24V at the fromt and 12V at the back. I just want to make sure so I don't cause any more problems for myself down the road.

Also, it apperas that the screen has two filaments. One thick and one thin. So in order to get a full glow should I wire the switch to both relays so I get current flowing to both of the filaments?

Lance

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87 HJ60
85 BJ74 LHD

Henry James the 47th · 01-06-09, 07:05 PM

The only test the FSM lists for the glow screen (intake heater) on a 12H-T, which I imagine would be very similar component to that in a 13B-T, is to check for continuity between the terminals of the intake heater and ground. No other specs are listed or considered - if there is no continuity, the intake heater needs to be replaced.

Hope that helps you.

By the way, is that a 24v truck? If so, you will need dual probes coming out of the '+' side of your meter to check for continuity properly, it would appear.

VE6LLZ · 01-07-09, 04:06 PM

The glow screen has continuity. I re-checked my relays and they check out good as well. I took another look at the FSM and noticed that it mentions another connector attached to the intake heater. I don't know how I missed that before. Turns out that when disconnected the pre-heat light on the dash is supposed to come back on after the pre-heat has cycled. Lo and behold that is exactly what was happening. I assumed that the pre-heat wasn't turning itself off and suspected a faulty glow timer.

I think I will abandon the momentary switch for the time being, re-hook everything up and see if the "superglow" system works like it is supposed to. Now that I have the power wires hooked up to the intake heater properly (which was my original problem, they were shorting out before) I hope everything will work properly.