In our experience, glow plug problems typically are caused, at least in part, by a failure in this harness. OEM part number 1807648C94. This is the original style glow plug harness for the 7.3L International engine. This harness should fit all early trucks that have the glow plug relay mounted on the rear of the intake manifold. Made in the USA
This is the correct glow plug harness for some Ford F-250 and Ford F350 trucks from the early 1990's. Some Ford F250 and Ford F350 Diesel used a 7.3L IDI prior to the re-branding of the Powerstroke, this harness is correct for these IDI motors. To our knowledge the IDI was used in Ford trucks up through 1993 or 1994. Because there have been some cases where this does not fit, the best thing to do is to remove your harness, take a good picture of it and e-mail it to us before you purchase so we can be 100% certain that it is exact.
The harness is built using the most common configuration. We have provided a detailed top of engine photograph so that you can compare it to your specific engine.