My truck is a 1993 F250, 7.3 diesel non-turbo.

When I turn the key to start my truck, the WTS light does not come on. It goes straight to the clicking sound, not giving the glow plugs a chance to warm up.

As a result, the engine is very hard starting. It will start eventually.

Things I've tried:
- Installed new glow plug controller.
- Replaced all glow plugs, and checked them with a continuity tester, all test fine.

After doing these things, the problem persists.

Any ideas what else I can do? Help would be appreciated.

 

remove and clean all connections on both the high current and low current circuits. the high current side gets it power from the long post on the start solenoid. this is a binding post for positive battery cable. the low current side gets power from the same circuit as the FSS, the controller reads the resistance of the Gp's if one or more of the Gp's is bad or has a corroded connection the controller go's in too a safety mode to protect remaining GP's. you must use feedback type GP's like the ZD9 or system will malfunction. and you must use correct relay, as it is a ungrounded type but it looks just like a common grounded type. this is a very common problem at part stores to pick get the wrong one and the controller fries or malfunctions leaving the gps on constantly. (I only buy controller's that come with relay) one should note that the timeing curcut of the controller times out after 2 mins and go's to sleep till the next time the key is turned off. immediate clicking, sounds like a short circuit or one or more dirty connection's at GP ... I can't stress enough how important it is to have good connection's and the bent z shaped current limiting resister must be installed and clean.