I did check all fuses and all conection , and fan comes on but only for 2-3 seconds an then shout down and stays shot for a minute then comes on again only for 2-3 seconds , all this time temperature is raising.If I conect two wires on the top of thermostat housing fan stay on all the times and then engine runs cool 79*C

Did you take off the top of the fuse box AND the cover?? IF so and all is well, you may have a faulty low speed resistor or a faulty fan clutch on the main fan. It should run well at temps near 100.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
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