Yes, if it is leaking and the coolant level is low.
Heater core
The HeaterTreater is an after market kit that solves heater and AC for the Jeep Grand Cherokee and Laredo. It is much cheaper than the dealership fix and is easy to install. For diagnosis and info, check out www.heatertreater.net or search eBay for "heatertreater".
There are several things that can cause heater problems in your 1998 Jeep Grain Cherokee. The most common cause of heater problems is low fluid in your cooling system.
if the rear ac is working then you probably have a damper door that is inoperative. this is in the heater/evaporator box. so if it isn't working then you will be heating and cooling at the same time out of the heater box.
Having the speedometer jump and the engine stall in the 1994 Jeep Grand Cherokee Laredo could be a problem with the idle and the transmission. The transmission slipping can cause the speedometer to jump.
Loose or worn out serpentine belt.
Pinched or blocked transmission cooling lines
Throttle position sensor
the switch board could be bad.
more than likely you have a short in your wiring
Most likely cause is an airlock in the cooling system
Yes