The fan will only run in low speed when the a/c is on.
The only time the fan will run in high speed is when the a/c fan high pressure switch is made.
Usually the high pressure switch will be closed when the a/c high side pressure gets over maybe 300 psi. When stuck in traffic and a/c full blast in Arizona heat.
When a/c is off, once engine temp gauge goes over half, the fan should run in low speed.
If it does not run in low speed with a/c off, there is a high speed fan relay with a normally closed contact that feeds the low speed relay.
The high speed relay closed contact could be bad.
Check the normally closed contact on the high speed fan relay first. __________________
1996 Ti 280k miles and still going....
1993 964 - holding on to this one
2001 Burban, 240k miles
2018 Suburban Z71
Last edited by bazar01; 11-29-2016 at 02:34 PM. |