HellCreek

Hi, The ISA functions manually, that is, I can make it extend and retract using a 9 volt battery wired directly to the motor.

C215_1 has 12.2 volts. It was the relay towards the cab. The one in the front is the fuel pump relay. This is backwards per the FSM. Since I switched both relays, they both should be good. ISA is still not working. Thanks, Tom

I swapped both relays for new ones, since I didn't know which one was which. The ISA still did not extend.

HI, Thanks. Actually, I did remove it from the throttle body, and the motor does extend and retract the shaft. It won't activate on the truck when I turn the key off though. Also, if I extend it manually, it won't retract and idle down on its own either.

Does any one know where the jumpers go?

When I said that I knew nothing about electronics, I meant it. I need to know the basics, like - connect one end of the jumper wire to "x" and the other end to "y".

I will check that when I get a chance. By the way, how do you jumper the diagnostic sockets (near the battery) to cycle the ISA motor? I'm having to do that at the motor itself. I can completely overhaul an engine, but I know nothing about electronics. Thanks, Tom

Thanks for fixing that. ISA, I stand corrected.

I know this topic has been beaten to death, but this one is a little strange. I changed my ISA with a new one, replaced my intake/exhaust gasket and torqued the bolts, changed all of the vacuum hoses, cleaned the TB and replaced all the gaskets and o-rings. The problem is, as the title suggests, the ISA is not working. It does not fully extend when I shut off the motor like it is supposed to. I can extend and retract the shaft with a 9 volt battery, so the motor is working. With the ISA unplugged, I have extended the shaft with a 9 volt battery, left it unplugged and started the engine. It revved up to 3500 RPM, so I shut off the engine, plugged the ISA back up and restarted the engine. The RPMs stayed at 3500 and would not come down. I took it for a test drive, and when I returned, the RPMs were still 3500. I order to be able to drive it, I unplugged the ISA, retracted the shaft with the 9 v battery, and the RPMs now are at 800. I hate it when things don't work properly, so I would really appreciate some help figuring this out. I suspect an electrical issue. I have already checked the Closed Throttle Switch, and it is in spec according to the FSM. This is a 1989 MJ Sporttruck with a 2.5L engine and a manual transmission. Thanks, Tom

Sorry, I hit the wrong key. I bought a new harness from Octane Lighting on eBay. It also has ceramic sockets. I works great, and my headlights are much brighter. Thanks, Tom

Thanks, Guys, I bought

Hi, Does anyone have a link for the headlight relay upgrade?

This is an awesome post. My headlights just quit working, and I would like to do the relay upgrade. Does anyone have a link for this? By the way, all of the other lights work and the driver's side high beam works, but no headlights.

Just an update. It has been two weeks, and the 25 amp fuse is holding, and the A/C works as it should. I guess it just doesn't like circuit breakers. Everything I did needed to be done, new blower motor, cleaning the contacts, refreshing the grounds, etc. Thanks for all of the help and suggestions. This is a great forum with a lot of helpful people.

Thanks, I will try that. Before I do, though, I would like to see how long that 25 amp fuse lasts.