Converting Coolant Switches

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   My dual mode coolant temperature switch failed again and I'm fed up with it to the point I want to convert it.

82 Concord, Spirit and Eagle use a single coolant switch (EF-3242254?2191) to control the electric manifold heater and the computer. The  computer side closes at 135F and the heater side opens at 160F, so there's two independent thermal switches inside.
Later models and it looks like the Jeeps changed to two switches (and there might of even been a conversion kit at one point as I've seen a harness adapter). The computer switch is EF-8933001979 (two wire, non grounding) and the manifold heater switch is EF-3242321 (one wire, grounding). I can find the heater switch listed as MOPAR J3242321 and the computer switch under several different part numbers (EG: NTK EF0073) but neither really matter if I don't know what the temperature rating is for either switch.  Besides buying a bunch of parts and testing each one in hot water does anyone know the specifications or which switches I should be looking for?

Edited by MIPS - Oct/09/2021 at 5:37pm

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
MIPS Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Mar/11/2019 Location: Kamloops, BC Status: Offline Points: 347	Post Options Post Reply Quote MIPS Report Post Thanks(0) Quote Reply Topic: Converting Coolant Switches Posted: Oct/09/2021 at 4:55pm
	My dual mode coolant temperature switch failed again and I'm fed up with it to the point I want to convert it. 82 Concord, Spirit and Eagle use a single coolant switch (EF-3242254?2191) to control the electric manifold heater and the computer. The computer side closes at 135F and the heater side opens at 160F, so there's two independent thermal switches inside. Later models and it looks like the Jeeps changed to two switches (and there might of even been a conversion kit at one point as I've seen a harness adapter). The computer switch is EF-8933001979 (two wire, non grounding) and the manifold heater switch is EF-3242321 (one wire, grounding). I can find the heater switch listed as MOPAR J3242321 and the computer switch under several different part numbers (EG: NTK EF0073) but neither really matter if I don't know what the temperature rating is for either switch. Besides buying a bunch of parts and testing each one in hot water does anyone know the specifications or which switches I should be looking for? Edited by MIPS - Oct/09/2021 at 5:37pm

FSJunkie Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4742	Post Options Post Reply Quote FSJunkie Report Post Thanks(0) Quote Reply Posted: Oct/10/2021 at 3:10am
	I've been through exactly what you are dealing with. I have a 1982 Concord and a 1984 Eagle. I was ready to convert the Concord to separate switches until I found a good used combined switch for it. The separate manifold heater switch and computer switch both operate at the same temperatures that the combined switch operates. It will close the contacts for the computer at 135 and open the ground for the manifold heater at 160. I think the 1982 cars were the only ones that used the combined switch.
	1955 Packard 1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited

MIPS Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Mar/11/2019 Location: Kamloops, BC Status: Offline Points: 347	Post Options Post Reply Quote MIPS Report Post Thanks(0) Quote Reply Posted: Oct/10/2021 at 1:12pm
	Awesome so I'll roll into the Lordco after the long weekend and get the sensors and pigtails for the harness conversion. I'm on my third sensor. These things are truly awful. First was a dud, the second one was used and also a dud and the third worked for about a year then over the summer I was getting abnormal knocking and the tester found the switch was jumping in and out so the computer was stuck thinking the engine was still cold and running the spark timing too advanced for a hot engine. I can't help but notice the '82 aluminum intake manifold does have the second port plugged off into the water jacket, so you don't have to drill and tap a new hole to thread anything in which is nice.

MIPS Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Mar/11/2019 Location: Kamloops, BC Status: Offline Points: 347	Post Options Post Reply Quote MIPS Report Post Thanks(0) Quote Reply Posted: Nov/16/2021 at 10:51pm
	So after some research and parts cross-referencing this diagram should list all the components and their part numbers needed to replace the single coolant temperature switch with a more reliable configuration. The harness adapter allows for spliceless installation and preserves all the connectors as-is.