Idiot Lights - Are They Working

[Griff04]

Another question. I’ve never had much confidence in “idiot lights”. With the ignition turned on shouldn’t both the lights on the left side be illuminated?? I know the top one is the temp, not sure about the bottom one?? Really concerned about the temp light. I did notice that as I actually start the vehicle with the key/starter engaged the temp light turns on but when the engine starts and the key is released it goes off. This may be a stupid question but I really don’t need issues that come along with overheating an engine. 

[Ωhm]

39 minutes ago, Griff04 said:

I did notice that as I actually start the vehicle with the key/starter engaged the temp light turns on but when the engine starts and the key is released it goes off.

This is known as 'bulb check'. Its purpose is to let you know the bulb is functioning (not burnt out). The ignition switch (G1) circuit grounds this bulb during engine cranking. This is normal. Also the brake light will do the same thing during engine cranking.

45 minutes ago, Griff04 said:

With the ignition turned on shouldn’t both the lights on the left side be illuminated?? I know the top one is the temp, not sure about the bottom one??

Temp light will illuminate during 'bulb check' (engine cranking) or when vehicle is overheated. Bottom is AMC advertising only.  

[Griff04]

5 minutes ago, Ωhm said:

This is known as 'bulb check'. Its purpose is to let you know the bulb is functioning (not burnt out). The ignition switch (G1) circuit grounds this bulb during engine cranking. This is normal. Also the brake light will do the same thing during engine cranking.

Temp light will illuminate during 'bulb check' (engine cranking) or when vehicle is overheated. Bottom is AMC advertising only.  

That makes me feel a lot better, at least I know it’s working. I’ll eventually install a separate temp and oil pressure gauge. 

 

Thanks for the info. 

 

Griff

[HOrnbrod]

14 minutes ago, Griff04 said:

That makes me feel a lot better, at least I know it’s working. I’ll eventually install a separate temp and oil pressure gauge. 

 

Thanks for the info. 

 

Griff

 

There's a better way. P/u a full gauge cluster from any 87-90 XJ/MJ and swap them out. It's plug 'n play. No rewiring, just stick it in the hole and connect the cables. Then swap out your coolant temp and oil pressure switches for the correct sensors, and you will have full gauges w. a tach.

[Griff04]

2 minutes ago, HOrnbrod said:

 

There's a better way. P/u a full gauge cluster from any 87-90 XJ/MJ and swap them out. It's plug 'n play. No rewiring, just stick it in the hole and connect the cables. Then swap out your coolant temp and oil pressure switches for the correct sensors, and you will have full gauges w. a tach.

That’s cool, gonna have to put that on my list too. 

 

Thx

Griff

[MeanLemons]

Yeah just don’t swap the gauges over to the old housing.  Lol

 

swap the whole thing as an unit. 

 

 

When you do the swap, make sure to change the coolant sender & oil pressure sensor